Air Helper kit for a Toyota Landcruiser with plus 2 inch suspension. These fit inside the rear coil springs to give extra support for load carrying and/or towing. You have to remove the bump stop in the middle of the rear spring, you'll need a 12mm socket with extension to do this. Then disconnect the bottom of the shock absorbers, plus a few other simple things, then lift the chassis so the axle drops down, then you can fit the new air spring and fittings inside the spring. The kit comes with air line and schrader valves etc.
This is very easy to install (about 2 or 3 hours) and will really improve your carrying ability.