The Grey Pneumatic 4031M is a 1" drive x 31mm standard length, 6-point metric impact socket. Key Technical Specifications Drive Size: 1" square drive Hex Size: 31 mm Socket Depth: Standard length Total Length (E): 60 mm Output Configuration: 6-Point hex Material: High-grade Chrome-Molybdenum alloy steel (Cr-Mo) Drive End Diameter (A): 51 mm Socket End Diameter (B): 48 mm Hex Depth (D): 21 mm Bolt Clearance Depth (C): 30 mm Weight: 1.19 lbs Compatible Retaining Accessories: O-Ring 4510, Pin 4520, Retiring Ring 4110