Introduction of the key: Right Select Key: Select key of menu M Menu Key: Long pre into menu setting Left Select Key: Long pre to turn on/off, Select key of menu Features:Type: Intelligent Solar TPMS Car Tire PreureSolar power charging, dont need to charge by connecting car cigarette lighterColorful LCD Digital displaying, clear to show tire informationRear-time monitoring preure & temperature of 4 tiresLow air preure/high temperature alarmHigh Temperature / Leakage / Low Battery AlarmIntelligent Shock Boot when car moving, dont need to turn on/offWirele connect by sensors, easy installTwo units (PSI / Bar) changeable, you can set the one you like.External Sensor:Easy to install, convenient to replaceBattery: built-in CR1632 button cellWorking voltage: 2.0 - 3.6VWorking environment: -30 ~105 Deg.CPreure accuracy: plus or minus 0.1barWaterproof grade: IP67Transmiion frequency: 433.92MHzMonitor:Battery type: 280mAh Li-ion batteryWorking voltage: 2.6-3.6VWorking environment: -20 ~70 Deg.CTransmiion frequency: 433.92MHzPreure unit: psi / barTemperature unit: Deg.C / Deg.FPackage Included:1 set Car Tyre Preure Monitoring System