Impact bit holder grade socket adapters are constructed from heat treated chrome vanadium steel; 3 sizes included: 1/4", 3/8" and 1/2" suitable for corresponding drills and drivers; The chamfered edges and spring-loaded detent ball will ensure a tight and secure fit, saving time; Flex Tech designed primarily for 1/4" hex shank for prolonged and high-torque applications; Coated with black phosphate ensuring rust-proof and corrosion-resistant protection