Tekton impact sockets are made from chromium vanadium steel that's heat-treated to 40-47 HRC for use on impact wrenches. The sockets are coated with a manganese phosphate finish to resist corrosion. The two-piece design of the Torx bit sockets allow us to optimize the steel alloys, heat treatments, and forming processes for the bit and socket separately, resulting in a tool that's higher performing and more durable than traditional one-piece designs. The two pieces are permanently press-fit together and won't loosen over time. The inside of the socket's drive end has smooth walls with no detent grooves to support engagement with drive tools that use friction ring anvils. A detent pin hole on one side of the drive end also supports engagement with detent pin anvil styles. This set includes a durable carrying case.