Each power drill socket adapter set is made of heat treated Chrome Vanadium steel with black phosphate Coating.Make sure all drill bit extension rust-proof and corrosion-resistant drill when use.The chamfered edges and spring-loaded detent ball will ensurea tight and secure fit,thus allowing you to finish repair tasks easliy and readuce work troubles.The drill bit extension has profession patened technology-TORSION FLEX TECH"designed for high-torque applications to flex and absorbt stress. All impact grade socket adapter set fit most screwdriver.You can use these socket adapter set to meet your various job needs, such as DIY motorcycle repair, car repair, carpentry, furniture installation and disassembly.Each Package Contents: 3pcs hex shank drill bit extension:1x 1/4", 1x 3/8", 1x 1/2" .All impact driver bit sets include a limited 1 year after-sales service.If you have any questions, please feel free to contact us,we will be the first time to solve for you.