1/2"-13 x 1-1/2" ASTM F835 Hex Drive Black Oxide Finish Alloy Steel Flat Socket Cap Screw / THREAD CLASS: 3A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 1.25 INCHES NOMINAL FASTENER LENGTH: 1.25 INCHES NOMINAL HEAD STYLE: C50 FLAT COUNTERSUNK HEAD DIAMETER: 0.806 INCHES MINIMUM AND 0.872 INCHES MAXIMUM HEAD HEIGHT: 0.251 INCHES NOMINAL INTERNAL DRIVE STYLE: D5 HEXAGON END ITEM IDENTIFICATION: MRAP-COUGAR NOMINAL THREAD DIAMETER: 0.500 INCHES WIDTH ACROSS FLATS: 0.312 INCHES MINIMUM AND 0.316 INCHES MAXIMUM THREAD QUANTITY PER INCH: 13 HARDNESS RATING: 39.0 ROCKWELL C MINIMUM OVERALL AND 44.0 ROCKWELL C MAXIMUM COLOR: BLACK OVERALL MATERIAL: STEEL OVERALL SURFACE TREATMENT: OXIDE OVERALL THREAD SERIES DESIGNATOR: UNC