Carriage Bolt, Inch, Neck Type Square, Basic Material Steel, Material Grade Grade 8, Fastener Finish Plain, Dia./Thread Size 5/8 In.-11, Fastener Length 9 in, Fastener Thread Direction Right Hand, Fastener Thread Type UNC (Coarse), ASME B18.5, SAE J429, Drill Size 41/64 in, Head Dia. 1.344 in, Head Height 21/64 in, Head Type Round, Square Height 0.344 in, Square Width 0.642 in, Tensile Strength 150,000 psi, For Use With Grade 8 Hex Nuts