5/16"-18 x 4-1/2" Grade 8 Yellow Zinc Finish Hex Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.880 INCHES NOMINAL FASTENER LENGTH: 4.450 INCHES NOMINAL HEAD STYLE: C1 HEXAGON HEAD HEIGHT: 0.203 INCHES NOMINAL WIDTH BETWEEN FLATS: 0.495 INCHES NOMINAL END ITEM IDENTIFICATION: R19TM900GPMFL NOMINAL THREAD DIAMETER: 0.312 INCHES THREAD QUANTITY PER INCH: 18 PART NAME ASSIGNED BY CONTROLLING AGENCY: HEX CAP SCREW, GRADE 8, YELLOW ZINC COLOR: YELLOW OVERALL MATERIAL: STEEL COMP 4140 OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: SAE J429 ASSN STD SINGLE MATERIAL RESPONSE OVERALL SURFACE TREATMENT: ZINC OVERALL SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM F1941 ASSN STD SINGLE TREATMENT RESPONSE OVERALL THREAD SERIES DESIGNATOR: UNC