Comparison Protester LL412R vs Protester LL305R

The number of vertical projections issued by the laser level during operation.

Most modern levels are designed for a strictly defined position when working; accordingly, the projection is called vertical, carried out from top to bottom relative to the standard position of the device. If there are several such planes, the level can be used for two or even three walls at once — this is useful, for example, for the simultaneous work of several people. At the same time, there are portable devices that can be used in different positions; for them, the main working plane is called vertical, although during operation it can be located both horizontally and at an angle, depending on specific tasks. Also note that the vertical projection can also give a horizontal line — for example, when installing a level on the floor.

Note that the number of projections is calculated not by geometric planes, but by individual laser elements, each of which is responsible for its own “work area”. For example, if the level has two vertical elements located at opposite ends and directed in different directions, they are considered as two projections even if these projections lie in the same plane.

The sweep angle in the vertical plane provided by the level emitter. If there are several such radiators (for example, on both sides of the case), this parameter is given for each of them separately.

The sweep angle is, in fact, the coverage angle, that is, the width of the sector captured by the emitter when the line is formed. The wider this angle, the more convenient the device is to use, the lower the likelihood that the device will have to be moved up and down to build a line. On the other hand, a larger sweep angle (at the same range) requires more power — and this, accordingly, affects the cost and power consumption.

The type and number of batteries used in the level/distance meter. All elements of standard sizes (AA, AAA, C, D, PP3) are available in two formats — disposable batteries and rechargeable batteries. This gives the user a choice: either buy relatively inexpensive batteries every time, or invest once in a rechargeable battery with a charger, and then simply charge the battery as needed. Branded batteries are, by definition, made only rechargeable, as are 18650 batteries.

Specific types of power today can be as follows:
— AA. A standard battery, known as a "finger battery". The power of these batteries is average, they can be used both in simple and quite advanced devices. This power supply is convenient due to the fact that AA batteries are very widespread and sold almost everywhere — due to this, finding and replacing them is usually not a problem.
— AAA. A smaller version of the AA element described above — almost identical in shape, but thinner and shorter. Such elements, known as "mini-finger" or "little fingers", have a rather low capacity and power, but are useful for portable devices, where compactness is crucial. They are also quite widespread.
— C. A cylindrical element, in the form of a rather thick "bar...rel" — with a length of 50 mm, the diameter is 26 mm. Due to its higher capacity and power than AA, it is better suited for advanced models with "long-range" lasers, but is less commonly used and generally less common.
— D. The largest and most capacious type of standard batteries found in modern levels and distance meter: thickness and diameter are 62 and 34 mm, respectively. The main area of application for D batteries is powerful professional devices.
— Rechargeable battery. In this case, the tool is powered by an branded battery that does not belong to any standard size. This option is good because such batteries are initially created for a specific model of the level/distance meter and are supplied in the set (and in some models they are made non-removable); in addition, their specifications can significantly exceed those of standard elements of a similar size and weight. On the other hand, such power source is less convenient when the charge runs out at the wrong moment: the only way to remedy the situation is usually to recharge, and it takes quite a long time (whereas standard batteries can be replaced in just a minute).
– 18650. The name of these batteries comes from their dimensions: 18.6x65.2 mm, cylindrical, outwardly they resemble somewhat enlarged AA batteries, but they have an operating voltage of about 3.7 V and a higher capacity. In addition, all 18650 type batteries are by definition not disposable, but rechargeable batteries (lithium-ion type).

— PP3. 9-volt batteries of a spesific rectangular shape, with a pair of contacts on one of the ends. Due to the high operating voltage, they provide high power and actual capacity, so one such battery is usually enough for operation.

— LR44. Miniature batteries of "coin" type, 11.6 mm in diameter and 5.4 mm thick. Usually installed in sets of 3 and are used in compact low-power laser levels, for which small size is more important than power and capacity. Note that specifically the LR44 marking refers to relatively inexpensive alkaline batteries; more expensive and advanced silver-zinc power supplies are referred to as SR44, or 357.

— 23A12V. A rather rare option: cylindrical batteries (length 29 mm, diameter 10 mm) with a nominal voltage of 12 V.

Connector type for synchronization with a smartphone and a computer or for charging the battery of the device.

Many modern levels and rangefinders are equipped with USB ports. The type of this interface is specified in this paragraph, but the options can be as follows:

- microUSB. Quite old, but still a very popular connector for portable gadgets. Slightly smaller than USB-C, it has an asymmetrical shape and a one-sided design.

- USB-C. The newest type of miniature USB connectors. Ports of this type are convenient primarily due to the symmetrical design, which allows you to insert the plug in either direction (unlike earlier standards, including microUSB). In addition, through USB-C, it is easier to implement many advanced features, in particular, fast charging technologies; however, it all depends on the specific model of the device.

We also note that both types of connectors are universal standards, a huge number of chargers, cables and adapters are produced for them. The presence of a USB port provides very extensive opportunities for synchronizing the level and rangefinder with a computer or mobile gadgets. As a rule, to use the possibilities of such a connection, you need to install special software from the manufacturer's website. Specific connectivity options may vary. In particular, it is not uncommon to find the function of downloading data from saved measurements to a PC.

A...t the same time, USB is used to charge the battery in the level / range finder: for this purpose, you can use an adapter for an outlet or car cigarette lighter, a portable power bank, a USB connector of a computer or laptop, the same port in an extension cord or even a wall outlet, etc. It comes to the point that some devices with a USB interface are completely supplied without a charger, with only one cable: it is assumed that it is not difficult to find a power connector for such a cable in our time.

Operating time of the device on one battery charge.

It is worth considering that these figures are quite approximate, since the operating time is measured under certain standard conditions (usually continuous operation at nominal power). And since in practice conditions may differ markedly, the operating time may turn out to be noticeably shorter or longer than stated. In addition, if the device uses replaceable batteries (AAA, AA and the like), then autonomy will also depend on the quality of the specific batteries/accumulators. Nevertheless, based on the data specified in the characteristics, it is quite possible to evaluate the capabilities of specific models and compare them with each other: the difference in the declared operating time, as a rule, proportionally corresponds to the difference in practical autonomy under the same conditions.

We also note that the operating time is specified mainly for levels; in rangefinders another parameter is more often used - the number of measurements (see below).

— holder. Devices for fixing the level / range finder on various surfaces. Such a device differs from a tripod primarily in its small size — within a couple of tens of centimeters. On the other hand, most holders allow you to install the device not only on horizontal, but also on vertical surfaces — for example, walls (and some are exclusively wall-mounted). Anyway, this function greatly expands the installation possibilities.

— Receiver. laser radiation supplied with the device. This device is usually equipped with laser levels, less often with rangefinders, and it is not required at all for optical instruments. The main purpose of the receiver is situations where the laser mark is not visible to the naked eye — for example, at a long distance or in bright light. More details on the features of its application are described above in the paragraph “Measurement range (with receiver)”.

— Tripod. Most modern instruments have a standard size thread and can be used with any suitable tripod. On the other hand, a complete tripod is most often specially designed for a certain model and optimally matches it in terms of general characteristics. In addition, this configuration option relieves you of the need to look for and purchase a suitable tripod yourself.

— Case / case. The main function of these devices is to protect...the device from bumps, scratches, dirt, temperature changes and other adverse effects; for this, of course, improvised means can also be used, but specialized protection is usually both more convenient and more reliable. In addition, almost all cases and most covers greatly simplify the transportation of the tool — in particular, due to the fact that they can also be used for complete accessories.

— Remote control. Among rangefinders and optical levels, this function is practically not found, because. working with them involves the constant stay of the device in the hands of the operator. But for laser levels that require you to regularly move from the device to the surface to be marked and back, the remote control can be a very useful addition — due to the fact that it minimizes such movements. For example, after marking the "front of work" on the wall according to the projection from the level, you do not have to approach the device to turn it off — just give a command from the remote control. At short distances, the savings in time and effort may not be so obvious, but over large areas, they can become quite noticeable.