For Exernal Torx Bolts. Seven sizes E-6 thru E-16. The three smaller sizes are 1/4" drive; the four larger sizes are 3/8" drive. Made of heat-treated alloy steel. Sockets are kept in a convenient vinyl holder. E-18 Torx Socket sold individually. Fits Ford under body cross members, rear wheel brakes on Thunderbirds and Cougars, and dual wheel Ford trucks. 1/2" drive. E-20 Torx Socket sold individually. Fits Cadillac Caterra camshaft and other applications. 1/2" drive.