The Powerbuilt Torx / Star Bit 7-Piece Socket Set features a 2-piece press-fit design for strength and durability. Socket bodies are constructed of Chrome Vanadium steel and mated to S-2 industrial-grade steel bits. The bits are precision ground for a tight fit on cap screws and other internal Torx / Star fasteners. Dual grease rings offer better grip and easier handling with greasy or dirty hands in almost any working environment. The set includes a metal socket rail to keep bits organized and together. Powerbuilt sockets meet or exceed ANSI standards and come with a lifetime warranty.