Socket Bit, Replaceable Insert No, SAE, Tip Size 5/16 in, Tip Style Slotted/ OVERALL LENGTH: 3.000 INCHES NOMINAL TIP WIDTH: 0.312 INCHES NOMINAL DRIVE SURFACE SIZE: 0.375 INCHES NOMINAL SINGLE END TIP THICKNESS: 0.040 INCHES NOMINAL FEATURES PROVIDED: MANUAL TOOL AND WRENCHING SURFACE SHAPE: FLAT (SLOTTED) SINGLE END EXTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: CHROMIUM DRIVE SURFACE SURFACE TREATMENT: OXIDE STYLE DESIGNATOR: 187A FLAT