Drop-forged; all plug-in heads = Rectangular shank with spring retaining pin. This ensures a solid and secure fit of the plug-in head in the torque wrench.
Chrome vanadium steel, chrome-plated.
Torque wrench with rectangular sockets.
Please note the pitch of the plug-in head and match this to that of the adjustment tool (see test certificate/operating instructions of the torque wrench you are using). If these vary, correct the pitch!