The Capri Tools ADVANCED SERIES sockets and bit sockets are made for the most demanding professionals. Crafted from custom forged premium steel, they undergo proprietary heat treatment and are precisely machined to perform in the toughest situations. The bits are forged with premium S2 steel. These S2 steel bits are exceptionally strong and durable; they withstand high torque and do not twist, protecting both the bit and the fastener. All bits have chamfered end to ensure a smooth fit onto fasteners. The sockets are made from premium Chrome Vanadium steel, plated with our SmartKrome protective plating for enhanced durability and corrosion resistance. These XZN/Triple Square bits are great for working with BMW, Mercedes, VW, Audi, Porsche, and most other European vehicles. Meets and exceeds ANSI standards . Organized in an impact-resistant tool case, include sizes in 1/4 in.: 4 mm, 5 mm, 6 mm; 3/8 in.: 8 mm, 9 mm, 10 mm; 1/2 in.: 12 mm, 14 mm, 16 mm, 18 mm.