Socket, 3/8 in Drive Size, 7/16 in Socket Size, 12-Point, Alloy Steel, Black Oxide Finish/ OVERALL LENGTH: 1.047 INCHES NOMINAL WRENCHING SURFACE SIZE: 0.438 INCHES NOMINAL SINGLE END DRIVE SURFACE SIZE: 0.375 INCHES NOMINAL SINGLE END FEATURES PROVIDED: MANUAL TOOL WRENCHING SURFACE SHAPE: 12 POINT SINGLE END INTERNAL DRIVE END SHAPE: SQUARE SINGLE END INTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: OXIDE OVERALL STYLE DESIGNATOR: 168 INTERNAL-INTERNAL