Introduction of the key: Right Select Key: Select key of menu M Menu Key: Long press into menu setting Left Select Key: Long press to turn on/off, Select key of menu Features: Type: Intelligent Solar TPMS Car Tire Pressure Solar power charging, dont need to charge by connecting car cigarette lighter Colorful LCD Digital displaying, clear to show tire information Rear-time monitoring pressure & temperature of 4 tires Low air pressure/high temperature alarm High Temperature / Leakage / Low Battery Alarm Intelligent Shock Boot when car moving, dont need to turn on/off Wireless connect by sensors, easy install Two units (PSI / Bar) changeable, you can set the one you like. External Sensor: Easy to install, convenient to replace Dust-Proof / Water-Proof / Anti-theft Anti High Temperate and Cold IP67 Protection / Waterproof Working Temperature: -20-85 Battery Life: 2 Years, replaceable Package Included: 1 set Car Tyre Pressure Monitoring System Do drop