Air Locker (RD166) by ARB®. Air locker locking differentials allow you to tackle the toughest terrain. The world’s premier traction aid, ARB air lockers keep you moving in all conditions. Created to provide 100% traction on demand, without sacrificing any of your vehicle’s highway driving performance, ARB Air Lockers employ a 12 volt ARB Air Compressor designed to activate (and deactivate) a solid and durable locking mechanism inside the differential. This gives you the traction you need, when you need it, all at the flip of a switch and all within the comfort of the driver’s seat.