A locking differential fixes both wheels on an axle to turn together, so the one with grip keeps pushing even if the other is in the air; it is for off-road use and is switched off on roads. A limited-slip differential works automatically, sending more torque to the wheel with grip when the other starts to slip. A brake locking differential gets a similar effect by braking the spinning wheel. The Thar Roxx 4x4 has both an electronic locking differential and brake locking.