SK Tools USA 1/4" Drive Standard Socket Set is made from heat treated chrome vanadium steel to ensure durability and extreme strength. The SuperKrome® plating delivers the toughest finish with a high-polish jewlry-like finish, providing long life and maximum corrosion resistance. The SureGrip(r) drive design drives the side of the fastener, not the corner, to provide increased strength and avoid rounding or damage to the fasteners. Set comes with an aluminum storage rail to keep sockets organized, ball bearings to secure them in place, and 360° rotating socket clips for easy identification and 4MM, 5MM, 6MM, 7MM, 8MM, 9MM, 10MM, 11MM, 12MM, 13MM, 14MM standard sockets with visible size markings and color-coded rings for easy identification. Your job isn't an easy one. It takes tough tools to get it done, but even the toughest tools can take a beating. That's why we stand behind a lifetime warranty on each of our products.