Box End Wrench, Alloy Steel, Satin, Head Size 5/16 in, 3/8 in, Overall Length 4 1/4 in, 15°/ OVERALL LENGTH: 4.250 INCHES MINIMUM AND 4.563 INCHES MAXIMUM WRENCHING SURFACE SIZE: 0.312 INCHES NOMINAL FIRST END WRENCHING SURFACE SIZE: 0.375 INCHES NOMINAL SECOND END WRENCHING SURFACE SHAPE: 12 POINT BOTH ENDS INTERNAL WRENCHING END OFFSET ANGLE: 15.0 DEGREES NOMINAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: CHROMIUM OVERALL STYLE DESIGNATOR: 41 ANGULAR OFFSET DOUBLE HEAD SPECIFICATION/STANDARD DATA: 81343-SAE AS954 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD NONDEFINITIVE SPEC/STD DATA: 2 TYPE AND 1 CLASS AND A STYLE