5/16"-18 x 1-1/2" Grade 8 ECOGUARD® Finish Hex Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.875 INCHES NOMINAL FASTENER LENGTH: 1.50 INCHES NOMINAL HEAD STYLE: C1 HEXAGON HEAD HEIGHT: 0.195 INCHES MINIMUM AND 0.211 INCHES MAXIMUM WIDTH BETWEEN FLATS: 0.489 INCHES MINIMUM AND 0.500 INCHES MAXIMUM END ITEM IDENTIFICATION: 2330-01-603-3559 NOMINAL THREAD DIAMETER: 0.3125 INCHES THREAD QUANTITY PER INCH: 18 PART NAME ASSIGNED BY CONTROLLING AGENCY: 5/16"-18X1-1/2" GRADE 8 ECOGUARD FINISH HEX CAP SCREW MATERIAL: STEEL OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: GRADE 8 STEEL PER SAE J429 NATIONAL STD/SPEC SINGLE MATERIAL RESPONSE OVERALL SURFACE TREATMENT: ZINC OVERALL AND ALUMINUM THREAD SERIES DESIGNATOR: UNC