Carriage Bolt Inch Neck Type Square Basic Material Steel Material Grade Grade 5 Fastener Finish Zinc Plated Dia/Thread Size 5/16 In.-18 Fastener Length 2 1/2 in Fastener Thread Direction Right Hand Fastener Thread Type UNC (Coarse) ASME B18.5 Drill Size 5/16 in Head Dia 0.688 in to 0.719 in Head Height 11/64 in Head Type Round Square Height 0.156 in to 0.187 in Square Width 0.307 in to 0.324 in Tensile Strength 120 000 psi Package Quantity 50