Comparison Casio PRW-3500-1 vs Casio Pro-Trek PRG-240-1

A caliber can be described as the type of movement used in a watch. It is expensive and impractical to design a unique movement for each watch model, so most manufacturers often use the same movement in different watch models, sometimes with significantly different designs. The term "caliber" is due to the fact that initially the type of movement was designated by a number (in inch lines) corresponding to its largest size; however, today unique names or alphanumeric indices that are not directly related to sizes are widely used.

Knowing the name of the caliber on which the watch you are interested in is built, you can, if desired, find more detailed information about the mechanism and determine how its characteristics meet your requirements.

The accuracy of the rate is usually determined by the largest error — the deviation from the reference time, which can occur in a month when the watch is constantly running in normal mode. Accordingly, the smaller the number in this paragraph, the more accurate the clock. In addition, the accuracy of the movement is a kind of status indicator: if the error exceeds the values stated in the characteristics, this may indicate a malfunction in the mechanism.

If the accuracy indicators are the same both in advance and in lag, one number is indicated in the characteristics — for example, 30 sec / month (i.e. +/-30 sec / month); however, many mechanisms have unequal deviations, for example -15/+25 sec/month. Also note that this parameter is relevant only for quartz watches (see “Movement type”): in mechanical models, the accuracy of the rate is noticeably lower, it is measured in seconds not per month, but per day.

An indicator showing how long the watch can run without winding, changing the battery, recharging, etc. It is found in models with any type of mechanism (see the relevant paragraph). Although the power reserve indicator is quite approximate, it still makes it easier to monitor the status of the device and reduces the risk of being left without a working watch at the wrong time.

Note that the End Of Life function (see below) in this case is not considered a power reserve indicator, although its role is generally similar.

— Alarm clock. A classic alarm clock is an audible signal that works at a time specified by the user. It can be used not only for getting up, but also as a reminder of a particular event. Note that in mechanical models (see "Type of mechanism") this function is almost never found.

— Stopwatch. A traditional stopwatch is a function that allows you to measure time intervals with an accuracy of seconds, or even fractions of a second. In modern watches, you can find two types of stopwatches. The first is the solutions used in models with displays (in other words, in watches with electronic and combined dials). In such devices, the countdown of seconds is displayed on the screen and is accurate to a tenth or even a hundredth of a second; Also, such stopwatches can have various additional functions: counting intermediate results for control points or laps, saving the results of the last measurement, etc.
The second type of stopwatch found in the arrow dials is the arrow on the main axis, which can be started and stopped at the request of the user. This is a rather rare option — for the reason that most often such an arrow is used in combination with additional scales and is no longer a stopwatch, but a chronograph (see below). And in watches where there are no chronograph scales, a rather unusual format for the operation of such a hand can be provided: in normal mode, it works like a standard second,...and when the watch is switched to stopwatch mode, it moves to zero and stops before the countdown begins.

— Timer. Countdown function; at the end of the countdown, an audible signal sounds. This function is convenient in cases where you need to measure a strictly defined period of time — for example, when cooking in the kitchen: “starting” the timer for the desired period is much more convenient than counting the hour you need to set the alarm.

— Day of the week. Ability to display the day of the week on the watch face. It is found both in watches with displays and in purely analogue models — they use a mechanical indicator for 7 days.

— Day of the month. The ability to display the current day of the month on the clock face. It can be either a number on the display or a mechanical indicator in the form of a window with a number. Note that in the latter case, regular adjustment of the calendar is required: the mechanical pointer is designed for 31 days, and if there are less than 31 days in the past month, the displayed date will have to be “scrolled” forward.

— Month of the year. Ability to display the current month on the watch face. Usually, it is combined with an indicator of the day of the month, and often also the day of the week; thus, the presence of this pointer means that the watch is equipped with a full-fledged calendar. Most often, the display is responsible for this function, but there are also purely arrow models with similar equipment. The month indicator of the year is often synchronized with the day indicator — so that the watch itself determines how many days are in the current month and after which day you need to switch to the first number.

— World time. The ability to use the clock to determine the time in other time zones than the current one. The specific way in which such a function is implemented may vary. Thus, the most popular option in hand models (see "Dial type") is the presence of an additional dial, on which the time of the time zone of interest is set. This format is convenient in cases where you constantly have to deal with a certain region — for example, to communicate with relatives or business partners from a particular country. Another option is the indexes on the rotating bezel (see below), corresponding to the main time zones of the world; to determine the world time, you need to turn the bezel so that the current time zone is opposite the hour hand — then the remaining marks will be opposite those divisions of the dial that correspond to the time in these time zones. This format is convenient for frequent change of time zones — in particular, it is found in watches for sailors. And models with digital dials usually provide switching the screen between the current and additional time zone (zones).


— 12/24 hour time format. This feature is indicated only for watches with pointer dials (and certain pointer-electronic models, see "Dial type"). It means that in addition to the main 12-hour scale, the watch also has a small dial with 24-hour markings. It allows you to determine what time the main scale shows — before or after noon: for example, at 6 pm the main dial will indicate 6 o'clock, the additional one — at 18 o'clock. — for example, in the conditions of a polar day / night, or during a long stay underground.
As for watches with electronic dials, even the 12-hour format is supplemented with the note "AM" or "PM" ("am" and "pm" respectively); for example, 20:00 would be 8:00 PM. So in such models there is simply no need to provide special functions for determining the time of day.

— The phases of the moon. The presence of an indicator in the watch that displays the current phase of the moon. Many processes on Earth depend on the phases of the Moon (in particular, the general physical and mental state of people), a number of signs are associated with them — not always 100% reliable, but not having an unequivocal refutation. A separate category of watches with a lunar calendar — "fishing" and "seafaring" models; the latter may even provide a separate tide calendar.

— Chronograph. Analogue of a stopwatch used in watches with pointer dials (see "Dial type"). Such watches have several additional small scales, each of which performs its own function. For example, one of these scales can be responsible for counting minutes (up to half an hour), the second — for counting hours (up to 12 hours), the third is the usual second hand, and the hand for counting seconds is located on the central axis and remains stationary until the chronograph is turned on.

— Tachymeter. A device for measuring the speed of movement by the time during which the measured section was passed. The tachymeter most often has the form of an additional scale for a stopwatch, and to measure the speed, you need to measure the time it takes to pass the control section with a stopwatch and see what number on the tachymeter scale the stopped arrow points to. In this case, the measurement time should not exceed a minute (otherwise the arrow will go to the second circle, and the readings will be unreliable), and additional calculations may be required to determine the final result. However, anyway, it is much more convenient to use tachymeter data to determine speed than stopwatch readings.

— Slide rule. Built-in mechanical calculator for some simple mathematical calculations, primarily multiplication and division. Such a device can be useful, in particular, for calculating travel time, fuel consumption, transferring money from one currency to another, etc. In hours, a slide rule usually consists of two rings with divisions (hence the second name for this function is a calculator ring ). One of these rings is motionless, and the second rotates freely; combining the marks on both scales according to certain rules, the user gets the desired result. Note that the slide rule is not as accurate as an electronic calculator and is more difficult to handle; on the other hand, with a minimum skill, elementary calculations on it can be carried out much faster than on the same calculator.

— Compass. A traditional compass is a device for determining cardinal directions. The accuracy of built-in compasses is usually not high, but they can be very useful for simple tasks or as a last resort when other navigational devices are not available.

— Altimeter (altimeter). A device for measuring the current height of the terrain. Often combined with a barometer (see below), in such cases the difference in pressure between the reference level and the current location is used to measure altitude. Technically, in this way it is possible to measure the height both above sea level and relative to a certain place taken as a standard; actual altimeter capabilities vary by watch model. Watches with this function are designed primarily for climbers and mountain hikers.

— Thermometer. Thermometers in watches are usually designed to measure the temperature of the surrounding air. This feature is found mainly in advanced sports models. It can be useful both for a general assessment of the environment, and for specific tasks such as weather forecasting, calculating the current altitude, etc.

— Barometer. A device for measuring atmospheric pressure. Data from the barometer allows you to assess the weather conditions and their favorableness for a certain type of activity — in particular, fishing. In addition, they can be used to predict changes in the weather: for example, a sharp drop in pressure is often a sign of an approaching storm. Also, the operation of the altimeter (see above) is often based precisely on the readings of the barometer.

— Bluetooth. The Bluetooth wireless interface is designed to communicate between various electronic devices over relatively short distances — up to 10 m. In wristwatches, it is mainly used to communicate with a smartphone or other gadget. The functionality of such a connection may be different, but anyway, it is much narrower than in smartwatches. The most popular features include displaying notifications from Facebook and/or Twitter on the watch, using the watch as a remote control for music or video, as well as setting the world time (determining the time zone from data from an external device).

— GPS module. Built-in satellite navigation module that allows you to determine the current geographic coordinates of the device. How this data is used may vary depending on the watch model. So, in some models, data on time zones in different countries are sewn in, and based on the current coordinates, the device can determine the exact local time. Another option is to record the routes (tracks) traveled. Some watches use GPS data for altimeter operation (see related paragraph). Models with Bluetooth may provide the ability to work as an external sensor for a smartphone or other gadget (it is believed that the hand position of the sensor improves accuracy). But it is difficult to provide full-fledged navigation in traditional watches; wearable gadgets with such functionality usually refer to either smartwatches or specialized navigators.

— Synchronization by radio channel. This function allows the watch to receive special time radio signals. These signals are transmitted over a special dedicated channel several times a day, and the exact time data is received from atomic chronometers used in scientific institutes. The error of such chronometers is 1 second for several thousand or even millions of years; accordingly, the accuracy of the clock synchronized with them is almost absolute. At the same time, note that precise time radio signals are not available in all countries of the world — so before buying such a watch, it's ok to check whether they will work in your region.

— Chronometer. In this case, the designation "chronometer" is used for high-precision models that are certified by the Swiss Chronometer Certification Centre (COSC). To obtain such a certificate, a watch must pass a fairly rigorous test, checking not only for overall accuracy, but also for the ability to maintain it with changes in case position and ambient temperature. At the same time, it should be noted that in fact "chronometric" accuracy is required extremely rarely, and it affects the cost of watches quite noticeably. So compliance with the COSC requirements is not so much a practically significant moment as an indicator of the high class of watches and the status of their owner.

— Pedometer. Built-in counter of the number of steps taken by the user. This feature is found predominantly on sport touring models equipped with Bluetooth (see above) and digital or combination watch faces (see "Dial Type"). To count steps, usually, data from the built-in accelerometer is used, and the measurement results can at least be transmitted to a smartphone or other gadget, and in some models they can also be displayed on their own screen. However, it's ok to clarify the specific features of the functionality of a watch with a pedometer separately.

— Phone search. Feature exclusive to Bluetooth models (see above). In accordance with the name, it facilitates the search for a “lost” phone located in close proximity (for example, forgotten in one of the home rooms): just give a command from the clock and the device will “respond” with a sound signal. Usually, to use this function, you need to install a special application (other additional functions are usually implemented through it, if available — for example, a pedometer).

The main colour of the watch case.

Modern watches are quite diverse in colour options. The most widespread models are in shades of " stainless steel ", golden and black ; however, in addition to this, on the market you can find, in particular, white, yellow, green, brown, red, orange, pink, silver, grey, blue and purple cases.

In general, the colour of the case is a fairly obvious parameter; Let's note only some of the nuances associated with marking:

— Multi-coloured models include models in which there is no clearly defined primary colour. If there is such a colour, it is indicated in the characteristics. And for two-tone cases, an additional colour can be specified, for example, "stainless steel with gold " or "black with blue "

— Silver, among other things, are plastic cases without additional coloring.

— "Stainless steel" in this case is a colour, not a material; other metals (e.g. alumin...ium and titanium) that are not complemented by PVD coating (see “Case Coating”) may have this shade. And the cases of gold watches, in turn, are not necessarily made of gold — red and white gold are also used in jewelry.

— Camouflage coloring is indicated separately — such watches are designated as "military", and here, again, the main shade of the coloring is given. However, not every military model has camouflage on the body; see below for details.

The rotating bezel is a swivel ring around the dial, with marks applied to it (ring).

Usually the bezel scale is similar to the minute/second scale of the dial, it is marked from 0 to 60, most often with marks every 5 or every 10 minutes (seconds). In such cases, this function is a somewhat simplified analogue of the timer or stopwatch / chronograph used in watches with analogue dials. To work in the stopwatch mode, you need to align the zero on the bezel with the position of the second or minute hand (depending on how long the period needs to be detected), and at the end of the measurement, look at what division on the bezel this hand has reached. To work in the timer mode, zero on the rotary scale is set at the end of the countdown, and the user can only monitor whether the arrow has reached zero. Thus, you can turn the watch into a timer or stopwatch mode with just one turn of the ring — it's faster and more convenient than digging into the settings. Such features are appreciated, in particular, by scuba divers who use a timer to control air supplies; at the same time, in diving watches, the rotation mechanism is often made one-sided, so that the bezel cannot be accidentally turned in the direction of increasing the remaining time.

There are other types of rotating bezels — for example, in the form of a scale with cardinal points used in watches with a compass.

As the name suggests, this parameter determines the degree of resistance of the watch to moisture. It is traditionally stated as the maximum depth under water at which the watch is able to remain watertight; however, it must be borne in mind that this number is very arbitrary. The fact is that when calculating the maximum immersion depth, only the static pressure of water is taken into account, that is, the pressure at complete immobility; at the same time, any movement creates dynamic pressure, which significantly increases the load on the body. In practice, this means that a mark of, for example, 50 m does not mean that you can dive to a depth of 50 m with a watch.

Modern water protection markings correspond to the following practical possibilities:

— 30 m(same as “Water Resistant” without any numbers). Entry level, drops of water are allowed, but not strong splashes. For example, such a watch can be left on in the rain or when washing, but when showering or washing a car, it should be left in a safe place. Of course, there is no talk of immersion in water.

- 50 m. Minimum water resistance, allowing the watch to be immersed in water. These watches can usually be used for swimming, and in some cases even jumping into the water (but not from towers), but they are not suitable for more serious tasks like surfing, snorkeling or scuba diving. As a rule, buttons are not allowed to be...used underwater.

- 100 m. This degree of water protection allows not only swimming, but also diving to shallow depths, however, it is still considered insufficient for surfing, jumping from towers and scuba diving.

- 200 m. Watches with such water protection are classified as “divers”; models and can withstand scuba diving to depths of up to 20 m.

- 300 m or more. Professional diving models suitable for diving to significant depths.

Please note that the characteristics described are approximate. Specific indicators of water resistance and the possibility of using the watch with water should be clarified according to the official data of the manufacturer.

Watches with increased resistance to low air temperatures.

Such conditions are not favorable for either mechanical or quartz watches: in "mechanics" cold changes the properties of individual parts and leads to desynchronization of the mechanism, and in quartz watches it can also accelerate battery discharge. To avoid these annoyances, modern watches may include various design features that reduce the likelihood of failures in cold weather. This is, at a minimum, improved thermal insulation of the case; and in models with hands (including quartz), special materials with a minimum coefficient of thermal expansion can also be used for individual parts of the movement.

Separately, it is worth recalling that watches are usually worn close to the body (hand), and in cold weather they are most often also covered with a sleeve of clothing — as a result, the temperature at the location of the watch is noticeably higher than that of the surrounding air. And additional thermal protection significantly affects the cost. Thus, it makes sense to specifically look for frost-resistant watches if they are planned to be used in a "harsh" environment — with frequent frosts of -30 °C and above, during mountaineering ascents, long (from several days) winter hikes, etc. n. And for everyday use in a relatively mild climate, ordinary, non-frost-resistant models are quite suitable.

The nominal size of a watch case in diameter (for round cases) or width (for other options, see "Case Shape"). In the most miniature modern models, this size is 21 – 25 mm or even less, among the largest there are cases of 46 – 50 mm and even larger.

Larger watches are more convenient in the sense that the dial readings are better visible on them, and it is easier to provide various additional functions in the design. On the other hand, small watches look neater and create less discomfort directly when worn. In addition, female models (see "Gender") are traditionally made more miniature than male ones. So the choice for this indicator depends mainly on the intended specifics of the application: for example, large cases are best suited for outdoor activities and tourism, about 41 – 45 mm in size, for household wear (regardless of gender) — about 31 – 35 mm, and as an accessory to an evening dress, a small watch of 30 mm or less would be more appropriate.

Also note that the size of a compatible strap/bracelet is associated with this indicator — see "Strap Width" for details.