To measure direction, obliquity, gradient, upright, milemeter, horizontal. Used in geology perambulation, colliery and other mine exploitation military training.
Pocket Compass Model DQL-8

Precision of long air level 15'±3'/2mm
precision of circle air level
30'±5'/2mm
The reading error
≤0.5°
Dial scale
1°
Weight
0.27kg
Size 80×70×35(mm)