The A1A monitors up to 22 tire positions, at up to 232 PSI, and is designed for RVs, Motorhomes, Trailers, 5th Wheels and Motor Coaches. Each one of those positions also updates on a consistent 4 minute update cycle. Not only do you get updated readings every four minutes, but the device also performs self-diagnostics every 5 seconds to instantly warn of unstable tire conditions. Besides pressure, the A1A will immediately alert if the internal tire pressure rises above 167 deg.F. It also features a single action search mode which pushes updates to the monitor in less than 10 minutes. The A1A also offers front or rear disconnect modes. Separating a towing vehicle from a towed trailer, 5th wheel, car, etc., is quick and easy. A simple press of two buttons allows for temporary disconnect as well as reconnect when the two pieces are re-united. The TM-A1A kits come with a booster (to eliminate electronic interference) 4 or 6 screw on transmitters, and much, much more (extra batteries, M) rings, bracket, locks, pouch, free lithium battery exchange program and unlimited (TM) phone/email support. TireMinder, the multi-year gold medal award winning TPMS!