TireMinder A1A Tire Pressure Monitoring System (TPMS) with 4 Transmitters for RVs, MotorHomes, 5th Wheels, Motor Coaches and Trailers Monitors up to 22 tires (0-232 PSI) 0.5 oz transmitters screw on valve stems Display PSI and temperature for each tire Visual and audible high/low pressure alarms Blow-out alarms