Dimensions meet the requirements of tooling standards ISO 691 / ISO 1711-1 / ASME B107.100 and aerospace standard SAE AS 954G. The 440 Pro Series was designed to ensure maximum user safety. When critical tightening torques are reached, the spanner is distorted gradually so no brutal breaking likely to injure the user. Tightening torques guaranteed significantly above specifications of strength tooling and bolting standards ISO 898-1 (quality class 12.9).