Abstract: An extension for use with the drive member of a socket wrench system includes a shaft having a coupling at its rear end for attaching the rear end to a socket drive member, and a stud at its front end for torque transferring engagement with a socket. A locking mechanism secures a socket to the stud. The locking components are operable between a first position for positively locking a socket to the stud and a second position for releasing a socket. The locking mechanism includes a central bore within the shaft and a radial cavity from the central bore through the stud. A detent in the radial cavity has a locking position wherein it protrudes out of the stud when the locking mechanism is in its locking position so as to engage a socket and prevent its removal from the stud. The detent has a releasing position wherein it resides substantially within the stud and partially within the axial bore. A locking bolt within the axial bore is axially moveable by a thumb lever for activating the detent.