A locking differential or locker is a variation on the standard automotive Differential (mechanics). A locking differential may provide increased Traction (engineering) compared to a standard, or "open" differential by restricting each of the two wheels on an axle to the same rotational speed without regard to available traction or differences in resistance seen at each wheel. A locked differential can provide a significant traction advantage over an open differential, but only when the traction under each wheel differs significantly.