The Ingersoll Rand® 3 piece 1/2" drive triple square XZN tamper-proof bit socket set includes bit sockets that use 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 .For added durability and corrosion resistance, bits are treated with a Zinc Phosphate finish. IR signature vertical knurling offers better grip and easier handling with greasy hands.