2-1/2" Class 150 Flange Bolt Kit ASTM A307 Grade A Zinc$10.99PriceOut of StockComplete Class 150 flange bolt kit for 2-1/2" ASME B16.5 flanges. Contents: (4) 5/8"-11 × 3" ASTM A307 Grade A Zinc-Plated Hex Machine Bolts and (4) 5/8"-11 Zinc Finish Hex Nuts.