5/16"-18 x 5/8" ASTM F593 18-8 Stainless Steel Hex Cap Screw / THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.625 INCHES NOMINAL FASTENER LENGTH: 0.625 INCHES NOMINAL HEAD STYLE: C1 HEXAGON END ITEM IDENTIFICATION: MRAP - UNIQUE NSN - USED ON 2 MRAP VARIANTS PART NAME ASSIGNED BY CONTROLLING AGENCY: BOLT,5/16-18 X 5/8 (SST)