The Channellock 171-pc Mechanic's Tool Set, No. 39053, is designed to be a strong, reliable tool set for automotive applications. The set includes 1/4", 3/8" and 1/2" 45 teeth ratchets; 20 1/4" sockets; 35 standard and deep 3/8" sockets; 12 1/2" sockets; two spark plug sockets; 3" extensions; a magnetic bit driver; 40 Philips slotted torx, pozi, square and hex driver bits; 20 SAE and Metric nut driver bits; 18 SAE and Metric hex keys; 12 SAE and Metric combo wrenches; and a magnetic parts tray. The entire set comes in a durable storage case.