The final automatic deflators come from CB Developments via Extreme Outback Products. These are some crazy little units that you can easily adjust from 3 to 13 psi with higher-pressure versions also available. To set the desired pressure, simply press down the plunger and turn to the setting. Then screw the deflators to your valve stem and a low whistling buzzing sound emanates from them till the pressure is reached. Though quick and easy to use, most deflators cannot be used during driving like the Trailhead and Staun versions, but the Extreme Outback is self-cleaning.
Other types of air-down tools are those that are installed permanently into the wheel. Advanced Air Systems, the makers of the Powertank CO2 tanks, offers the Monster Deflator Valves that thread into a larger hole than the standard valve stem. This 71/416-inch hole must be drilled and tapped into your wheels and it is suggested to do it opposite the stock valve. Once the 11/44-18 pipe thread hole is ready and the new valve is in place, you can simply unscrew the red locking ring and it opens up four 11/48-inch holes to allow quick airing down.
Not only do the Monster Valves air down quickly, they can also be aired up quicker since the larger stems allow more airflow, and they come with a big adapter fitting to go from a standard air line to the monster valves. Plus, since your wheel now has two valve stems, you can check the pressure on the stock stem while airing up or down on the monster valve.
The Rapid Air Down valve stem must be installed on the wheel prior to mounting the tires. They can be aired up conventionally, but then to air down simply unscrew the big grooved nut and let the air escape through the holes in the body of the valve. Though previously made by Klune-V, these are currently available through Trail Ready and Quadratec.