Manufactured from S2 steel, the OTC Master Torx Socket Set, No. 5900A, combines four of the most popular styles of Torx socket sets into a 52-piece, professional grade master set. The set includes hard-to-find Torx Plus bit sockets, as well as the T47 for seatbelt anchors; the T55 bit 3/8" drive for calipers and engine mounting bolts; and the T70 used on Subaru torque converter drain plugs and GM truck brake rotor retaining bolts that most kits lack. All bit sockets are a two-piece design and vary in size ranging from the standard 1/4" square drive, and larger bits suitable for 3/8" and 1/2" drive sockets.