Impact Universal Joint, Black Oxide, Locking No, Overall Length 3 1/2 in/ OVERALL LENGTH: 4.094 INCHES NOMINAL DRIVE SURFACE SIZE: 0.750 INCHES NOMINAL BOTH ENDS FEATURES PROVIDED: POWER TOOL DRIVE END SHAPE: SQUARE FIRST END INTERNAL DRIVE END SHAPE: SQUARE SECOND END EXTERNAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: OXIDE OVERALL STYLE DESIGNATOR: 208 EXTERNAL-INTERNAL SPECIFICATION/STANDARD DATA: 05047-ASME B107.2 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD NONDEFINITIVE SPEC/STD DATA: 6 TYPE