Truck Car TPMS Tire Pressure Monitoring System Auto Display Alarm Monitoring USB Charging Temperature Alert With 6 Sensors Specifications and functions - Just plug it into the car"'"s cigarette lighter, drive the car, and it will open automatically. In addition, it has a USB charging port on the outside, which can charge your USB devices, such as mobile phones and tablets -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 -Wireless connect by sensors, easy install -Build-in sensors and external sensors options, meets all your need -Fit on almost 98% cars on market External Sensors(Optional) -Easy to install, convenient to replace -Dust-Proof / Water-Proof / Anti-theft -Anti High Temperate and Cold -IP67 Protection / Waterproof -Working Temperature: -10-85 -Battery Life: 2 Years, replaceable How to replace the External Sensor battery? 1. Remove the dismantling gasket 2. Wrench the shell with a wrench 3. Remove the battery 4. Replace a new battery. There are 3 types.pls choose the correct one you like.