Impact Socket, Socket Size 5/16 in, Socket Shape 6-Point, Drive Type Impact, Drive Size 3/8 in/ OVERALL LENGTH: 2.750 INCHES NOMINAL WRENCHING SURFACE SIZE: 0.312 INCHES NOMINAL SINGLE END DRIVE SURFACE SIZE: 0.375 INCHES NOMINAL SINGLE END FEATURES PROVIDED: POWER TOOL WRENCHING SURFACE SHAPE: 6 POINT SINGLE END INTERNAL DRIVE END SHAPE: SQUARE SINGLE END INTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: OXIDE OVERALL STYLE DESIGNATOR: 168 INTERNAL-INTERNAL