6. The new ARB Air Locker is a two-piece carrier fitted with a pneumatic ring sandwiched between the carrier bearing and differential. It is a relatively easy unit to assemble-you simply pull the two halves of the carrier apart, and bolt the bull gear in between. Being the first selectable locker available for the 2 1/2-ton top loader, steering no longer has to be an epic battle on the trail. With a flick of a switch you go from completely open to 100-percent locked.