J&R Quality Tools XZN Triple Square Spline Bit Socket Set, S2 Steel | 10-Piece Set DURABILITY: bits made of premium S2 alloy steel for superior hardness that reduce wear-outs and insure longevity TORQUE STRENGTH: high strength chrome vanadium steel sockets provide superior torque for greater turning power with mirror chrome finish for corrosion resistance PRECISION BITS: precisely and automatically machined bit tips to ensure accurate size, chamfered bit ends insert smoothly into fasteners and protect both bits and fasteners from damaged edges ORGANIZED STORAGE: set includes a sturdy plastic organizing case for secure storage and easy carrying 10-Piece XZN triple square spline bit socket set includes: 1/4" Drive: 4mm, 5mm, 6mm; 3/8" Drive: 8mm, 9mm, 10mm, 12mm, 14mm (tamper proof); 1/2" Drive: 16mm (tamper proof), 18mm (tamper proof)