Smittybilt's Rapid Air Deflator (R.A.D.) accurately and rapidly reduces tire pressure in seconds, taking the guess work out of airing down. The Smittybilt Tire Deflators are fully adjustable to air down in increments of 3 PSI. Tire pressure can be aired down to 8 PSI. No tools required to adjust, made from 100 Percent Quality Brass. The Smittybilt Tire Deflators are one of the fastest in the market today!