The Spartan Locker, by USA Standard Gear, provides reliable traction at a low cost. The Spartan locker's design does not use the thrust washers and has a revolutionary spring and pin design that makes installation a snap!This automatic locker replaces the stock side and pinion gears while utilizing the factory open differential case. A new and stronger center pin fits in oval slots between two inner drivers. Under load the center pin forces the inner drivers outward to engage the outer axle couplers on each side of the case. This provides locked power to both drive wheels, providing greater traction. When turning, one driver is unloaded and the teeth can ratchet across each other creating differential action to reduce tire wear and make turning the vehicle easier. This is one of the most economical lockers on the market today.