A socket-wrench set, was a kit of tools containing a socket-wrench and assorted sockets. The socket-wrench, more commonly referred to as a ratchet-wrench, was a type of wrench, or tightening tool, that used separate, removable sockets to fit many different sizes of fittings and fasteners, most commonly nuts and bolts. The socket-wrench included a ratcheting mechanism that allowed the nut to be tightened or loosened with a reciprocating motion, without requiring that the wrench be removed and refitted after each turn. Typically, a small lever behind the socket switches the wrench between tightening and loosening mode. The sockets were attached to the ratchet through a square fitting that contains a spring loaded ball detent mechanism to keep the sockets in place. The advantage of the socket