Air locker locking differentials allow you to tackle the toughest terrain. The worlds premier traction aid, ARB air lockers keep you moving in all conditions.A complete air locker kit: replacement differential, activation switch, solenoid valve, air line and bulkhead fittings. ARB Air Locker Differential; Shaft Spline 35; Ratio 4.10 And Down; Dana 60HD; S/N.........