A round head bolt with a square neck under the head and a unified thread pitch. Designed to keep the bolt from turning when a nut is being tightened. The short neck variety is used in sheet metal where a standard sized neck would create an obstruction. Stainless Steels Material Grade : 304, 304B, 309, 310, 316, 316B, 317, 317L, 321, 347, 401, 416, 430 & 501. Diameter: M12 to M64 up to 1200 MM in Length Duplex & Super Duplex : UNS31803, S32750. Diameter: M12 to M64 up to 1200 MM in Length Hastelloy: Hastelloy C-276, Hastelloy C-22. Diameter: M12 to M64 up to 1200 MM in Length Exotics: 904L, A-286, Alloy20, Alloy50, NitronicAlloys50, Titanium. Diameter: M12 to M64 up to 1200 MM in Length Nickel Alloys : Inconel600, 601, 625, 718, 750, 800/800H, 825, 925, Monel 400, 405, K-500 & Nickel 200. Diameter: M12 to M64 up to 1200 MM in Length HIGH TENSILE Grade 8.8/10.9/12.9/B7