Greatly increase your traction when offroad with these deflators. Machined from solid brass, these little deflators are easy to use and very accurate. Set-up is easy too. The kit includes four (4) deflators and a durable storage pouch for storage. Just screw them on to the tire valve stem and walk away. They automatically stop bleeding air when it gets to the pre-set pressure. They are adjustable from 4 to 56 PSI and are the most sensitive automatic deflators on the market and they are built to last and come with a LIFETIME WARRANTY!