Air Helper kit for a Toyota Colorado / Prado . These fit inside the rear coil springs to give extra support for load carrying and/or towing. You'll need to 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.