indicating type. the measuring element is a torsional leaf spring. clockwise tightening (with trailing pointer) and anticlockwise tightening. with 1/4" internal hex drive (F 6.3 DIN 3126). comparative scale in in.lb and cursor. inserts and adaptors with external hex E 6.3 (1/4") DIN 3126/ISO 1173 are securely held and firmly controlled in the mounting shaft. to attach 1/4" sockets, please order adaptor No 3115. display deviation value ± 4%.