9/16"-18 x 5-1/2" Grade 5 Zinc Finish Hex Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 1.375 INCHES NOMINAL FASTENER LENGTH: 5.400 INCHES MINIMUM AND 5.500 INCHES MAXIMUM HEAD STYLE: C1 HEXAGON HEAD HEIGHT: 0.348 INCHES MINIMUM AND 0.371 INCHES MAXIMUM WIDTH BETWEEN FLATS: 0.798 INCHES MINIMUM AND 0.812 INCHES MAXIMUM END ITEM IDENTIFICATION: MRAP; COUGAR E1U NOMINAL THREAD DIAMETER: 0.563 INCHES THREAD QUANTITY PER INCH: 18 MATERIAL: STEEL OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: SAE J429, GRADE 5 ASSN STD SINGLE MATERIAL RESPONSE OVERALL SURFACE TREATMENT: ZINC OVERALL SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM F1941, FE/ZN 3A ASSN STD SINGLE TREATMENT RESPONSE OVERALL THREAD SERIES DESIGNATOR: UNF