Alloy Steel, Quenched and Tempered Minimum Tensile Strength of 150,000 PSI 1/4-20 x 1-1/2" USS Coarse Thread Yellow Chromate Zinc Coating 50 Pieces 1/4-20 x 1-1/2" Hex Head Cap Screw, Grade 8 hardened bolt. Pack of 50. USS Coarse thread. Very good strength. Great for heavy machinery and automotive applications. Where high strength is a must!