Comparison Bosch GLL 2-15 G Professional 0601063W02 vs Bosch GCL 2-15 Professional 0601066E02

The standard size of the thread used to mount the level/rangefinder on a tripod (if available). This option can be useful if you already have a surveying tripod that you want to use with the tool.

The most popular options in modern devices are 1/4" and 5/8". It is worth noting that 1/4" is a standard size for photographic equipment - accordingly, levels with such a thread can be installed even on ordinary photographic tripods.

The time after which the device turns off by itself completely if the user does not perform any action.

See above for more information on auto power off; and his time has a double meaning. On the one hand, if this time is short, then the idle time of the device will be minimal, which helps to save energy. On the other hand, too frequent auto-shutdown (with subsequent switching on for work) is also undesirable — it increases the wear of components and reduces the resource, and it is not always convenient for the user. So manufacturers choose the time, taking into account the balance between these moments, as well as the general class and purpose of the device. So, in some rangefinders, this indicator does not even reach a minute, although in most such devices it is in the range from 3 to 8 minutes; and in some professional devices (primarily levels), the auto-off time can be 30 minutes or more (up to 3 hours).

The wavelength of the radiation emitted by the LED of the level or rangefinder; this parameter determines primarily the colour of the laser beam. The most widespread in modern models are LEDs with a wavelength of about 635 nm — at a relatively low cost, they provide bright red radiation, giving a well-visible projection. There are also green lasers, usually at 532 nm — the marks from them are even better visible, but such LEDs are quite expensive and rarely used. And radiation with a wave longer than 780 nm belongs to the infrared spectrum. Such a laser is invisible to the naked eye and is poorly suited for leveling, but it can be used in rangefinders — of course, with a viewfinder (see "Type" for more details).

The color of the laser beam emitted by the device.

Red lasers are the most popular in our time: they are relatively inexpensive, while they are quite effective and functional, and also quite noticeable on most surfaces. In turn, green lasers are better visible to the human eye (with the same emitter power); however, they are noticeably more expensive than red ones, consume more energy and have a shorter service life, and therefore are much less common.

Blue lines are rarely seen in laser instruments. Their competitive advantage over traditional green and red lasers is their high brightness, which ensures excellent visibility of the beams on many surfaces, incl. when doing outdoor work.

In some devices, you can find two types of lasers at once - both red and green. As a rule, these are levels with several projections, where green is used to build planes, and red is used for point projections.

The number of individual points projected by the laser tool — rangefinder or level, see "Type" — when working. In the first case, one point projection is standardly provided — more is simply not required to measure distances. In levels, there can be several points, and some models do not have planar projections at all and work only with points. This format may not be as convenient as displaying lines; at the same time, with the same laser power, dot marks shine brighter and are more visible, especially at long distances. In addition, there are certain types of work for which point projection is considered optimal — for example, laying sewers, determining the locations for two holes in opposite walls, etc.

Zenith in this case is called a point projection directed vertically upwards.

By itself, such a projection can be useful, for example, if you need to make holes in several floors, located strictly one above the other. It is enough to point the "anti-aircraft" laser at the hole located directly above it — and the mark from the beam that passed through this hole will indicate the point for the hole on the next floor. And if the device also has the nadir function (see below), then the combination of these functions will be very convenient for marking the floor and ceiling at the same time — for racks, partitions, etc.: marks from the zenith and nadir are located strictly one above the other.

Nadir in this case is called a point projection directed vertically down.

By itself, such a projection can be used, in particular, for making holes on the same vertical in ceilings located at different levels. It is enough to make one of the holes, install a level above it — and the laser beam going vertically downwards will indicate the location of the next hole. And in devices that also have the zenith function (see above), the marks from the zenith and nadir projections are located strictly one above the other. This is very convenient when marking the floor and ceiling at the same time for racks, partitions, etc.

The level of protection against harmful influences (in the first place — the penetration of foreign objects) that the body of the level / rangefinder provides in accordance with the IP standard. This standard describes two separate characteristics — protection against solid objects and against water. They are designated respectively by the first and second digit after the IP index; the higher the number, the higher the degree of protection.

Considering that levels and rangefinders usually have to work on construction sites where there is a lot of dust, the minimum level of protection against solid objects for such tools is the fifth. It allows some dust to get inside, but in such a way that it does not affect the performance of the device. The maximum level of dust resistance is 6, which implies complete protection from solid particles.

The second characteristic, protection against moisture, in levels and rangefinders is usually indicated starting from level 4. Officially, it provides protection "against spray from any direction", in fact this means that it can be used in moderate rain with strong winds — a useful point in that if the tool is to be used outdoors. Level 5 allows operation during storms and downpours, a device of the sixth class can withstand being hit by a wave, the seventh — a short-term immersion under water up to 1 m, and the eighth — even a long stay under water. However, for a conventional construction tool, too high water resistance i...s usually not required.

Actually, the most popular option in modern construction tools is the IP54 class: it is quite enough even for work in bad weather, while such cases are relatively inexpensive. There are also more protected models, but less often.

It is also worth noting that a certain level of dust and water protection in itself is usually provided even in devices that do not have an IP marking. The absence of this index does not necessarily mean the absence of protection — it only says that the case has not been officially certified according to the IP standard. But if you need an additional guarantee of reliability, you should still pay attention to certified options.

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.