DURABLE: This 3 piece socket driver set is made from strong chrome vanadium steel for durability. SIZES: With a 1/4″ quick change hex shank, it includes sizes ¼" x 65mm, 3/8 inch x 65mm and ½ inch x 72mm. SECURE ACTION: A spring loaded ball bearing head holds the sockets more securely. Contents: 1/4" x 65mm; 3/8" x 65mm; 1/2" x 72mm.