TRE air locker takes you mountain takes you home TRE air locker features Provides 100% traction on demand Push button traction Strongest materials used in construction, Differential Case- made from forged 8620 steel, Gears-made from 4320 chromoly alloy steel Front & rear Air Lockers available for most car models Both available for 4 wheel drive and 2 wheel drive applications Easy installation, maintenance-no special tools or skills required Extra 4mm airline equipped aim to eliminate the risk of oil being pumped up the airline Recessed coloured LED switches show clearly when TRE Air Locker is on or off