Powertrax Lock-Right performance lockers straight-line performance is equal to a solid spool axle, yet they automatically unlock during turns. When extreme traction output and high-strength are required, racers, hot-rodders and muscle car owners chose Lock-Right lockers! Best suited for extreme off-road to severe on-road use, Powertrax lockers replace the spider gears in your differential carrier without affecting your ring and pinion settings. The whole job can be done in your driveway with common hand tools in a couple of hours. A carrier is not included.