BSW 5/16"-18 1/4"-20 Black 12.9 High Tensile Allen Bolts Socket Cap Screws. 【Thread type】: BSW. 【Size】: 5/16-18 1/2, 5/16-18 5/8, 5/16-18 3/4, 5/16-18 1, 5/16-18 1-1/4, 5/16-18 1-1/2, 5/16-18 1-3/4, 5/16-18 2, 5/16-18 2-1/4, 5/16-18 2-1/2, 5/16-18 2-3/4, 5/16-18 3, 5/16-18 3-1/4, 5/16-18 3-1/2, 5/16-18 4, 5/16-18 4-1/2, 5/16-18 5, 1/4-20 3/8, 1/4-20 1/2, 1/4-20 5/8, 1/4-20 3/4, 1/4-20 1, 1/4-20 1-1/4, 1/4-20 1-1/2, 1/4-20 1-3/4, 1/4-20 2, 1/4-20 2-1/4, 1/4-20 2-1/2, 1/4-20 2-3/4, 1/4-20 3, 1/4-20 3-1/4, 1/4-20 3-1/2, 1/4-20 4.
eBay