To determine the size of the helmet-mask of GP-5,RSH-4, PBF, PMG, GP-5, use one of these methods. The first method involves two measurements of head. Take a tape measure. Apply the tape beginning at the temporal part of the head and lead it along a closed line which passes through the top.
Connecting the free end of the tape from its beginning, will continue the measurement by lowering a tape from the temporal part on the cheek to the chin and let the tape up to the second temple. Thus, you will get the first result that you want to remember. The second result you can get, having the dimension along the line that connects the circle hole passes through the ears and eyebrows.
Total the results of both measurements and determine the size of the mask in accordance with the specified data. If the result is less than 92 cm – size 0; from 92 to 95.5 – size 1; from of 95.5 to 99 – size 2; from 99 to 102,5 – size 3; more 102,5 – size 4.
The second method involves the measurement of the head only along a closed line which passes through the crown, cheeks and chin. Determine the size of the mask according to the specified data. If the result is less than 63.5 cm – size 0; from 63.5 to 65.5 – size 1; from of 66.0 to 68.0 - size 2; from of 68.5 to 70.5 – size 3; more than 71.0 per size 4.
For gas masks PMK and GP-7, which is further provided with adjustable elastics in the back, there are three size of the front part. To determine size, measure with measuring tape horizontal head circumference at the level of the forehead. The same method is used in determining the head size when purchasing caps and other headgear.
Determine the size of the mask according to the specified data. If the result is less than 56 cm size 1; 56 to 60 – size 2; more than 60 size 3.