Box End Wrench, Alloy Steel, Chrome, Head Size 16 mm, 18 mm, Overall Length 8 in, 0°/ OVERALL LENGTH: 206.0 MILLIMETERS NOMINAL WRENCHING SURFACE SIZE: 16.0 MILLIMETERS NOMINAL FIRST END WRENCHING SURFACE SIZE: 18.0 MILLIMETERS NOMINAL SECOND END WRENCHING SURFACE SHAPE: 12 POINT BOTH ENDS INTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: CHROMIUM OVERALL STYLE DESIGNATOR: 144 STRAIGHT DOUBLE HEAD