These tough Tamper Proof Star bit sockets are built for the toughest jobs. Powerbuilt 1/4 Inch Drive T-20 Tamper Proof Star Bit Socket features a 2-piece press-fit design for strength and durability. Socket bodies are constructed of tough Chrome Vanadium Steel and mated to S-2 industrial-grade steel bits which ensure a lifetime of reliable use. The hardened S2 steel bits are precision ground for a tight fit onto Tamper-proof Torx Star fasteners. The bit’s Zinc Phosphate coating allows for a protective non-slip function preventing bolts from striping. High visibility sizing is stamped into the mirror-polished Chrome Vanadium sockets.