Working length of the tool. The meaning of this parameter may be different, depending on the type (see above) and design features. So, for bubble levels, rules and inclinometers, the total length is indicated, while in sliding models (see "Functions") data are given for the maximum length, unfolded. For goniometers, on the contrary, the length is indicated by the size of the main bar, that is, in the folded state; and for hydraulic levels, a slightly different parameter is used — the length of the hose, it is given separately (see below).
In general, the longer the tool — the larger the surface it can measure or (in the case of rules) process, the more advanced and professional this model is considered. On the other hand, a longer fixture will also be more expensive and cumbersome, and in cramped conditions, problems may arise up to the complete impossibility of use. Therefore, when choosing, you need to take into account the specifics of the work and the scale of the proposed measurements. For example, for ordinary home repairs, a level of 40 – 50 cm is quite enough, for the construction of a small extension, you should choose a larger model, by 70 – 80 centimeters, and the length of high-quality bubble levels
can exceed 3 m. At the same time, very small instruments of this type are also produced — from 7 cm. Such
pocket levels can be useful, for example, for calibrating a geodetic instrument that
...does not have its own alignment tools. And you can carry it in your pocket, bag, tool box. But the rules, by definition, are made long — from 1 m.