Bits made from premium S2 alloy steel for superior hardness that reduces wear-out and ensures longevity. High strength chrome vanadium sockets provide superior torque for greater turning power and a mirror chrome finish for corrosion resistance. The 4-1/4 inch (110mm) extra-long shaft extends reach to fasteners in deep and tight spots. Precisely machined ball end ensures accurate tip size and allows access to fasteners from multiple angles to get around obstructions. Set includes a heavy-duty storage case and 7 pieces of 3/8 inch drive metric hex bit sockets: 3, 4, 5, 6, 7, 8, 10mm.