Does not fit Standard JK Carrier -- Use 706008X carrier The Spartan Locker, by USA Standard Gear, provides reliable traction at a low cost. Give your vehicle great traction and save some cash. Choose a Spartan Locker for better traction. The Spartan locker by USA standard gear is a mechanical locker that replaces the spiders in a standard open case, will not work in a posi carrier. The Spartan locker's design does not use the thrust washers and has a revolutionary spring and pin design that makes installation a snap! The couplers and drivers are made from 9310 steel, for added strength. Each Spartan locker carries a one year warranty against defect.