Box End Wrench, Alloy Steel, Chrome, Head Size 1/4 in, 5/16 in, Overall Length 4 1/2 in, 0°/ OVERALL LENGTH: 4.281 INCHES NOMINAL WRENCHING SURFACE SIZE: 0.250 INCHES NOMINAL FIRST END WRENCHING SURFACE SIZE: 0.312 INCHES NOMINAL SECOND END WRENCHING SURFACE SHAPE: 6 POINT BOTH ENDS INTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: CHROMIUM OVERALL STYLE DESIGNATOR: 144 STRAIGHT DOUBLE HEAD