OTC 6191 TP50 Torx Plus 3/8" Square Drive Socket
This is one of many torx "plus" bit sockets from OTC, it's separate, however, they do come in a set.  This particular one is a TP50 (torx plus) with a 3/8" drive.  It's made of S2 steel to meet or exceed torque specifications.  The two-piece design makes it stronger and allows for a longer life.  Backed by OTC's lifetime marathon warranty.