Armstrong 64-750 7 Piece 3/8" Drive 12 Point SAE Torque Wrench Adapter Set Changes A 3/8" Square Drive Torque Wrench (Or Ratchet) Into A 12-Pt. Box End Wrench Configuration The Box End Wall Thickness is Specially Designed to Provide Strength While Still Allowing Ample Room for Access to Reach Restricted Fasteners. Measure Exactly 2 Inches From Center of Adapter Opening (Fastener) to the Center of Square Drive for Easy Torque Calculations Formula to Determine Torque Wrench Setting Using A Torque Adapter This Calculation Assumes That the Attachment is Aligned with Torque Wrench Handle When Torqueing Fastener