Note :If you need to purchase more than one, please contact us, we can give you the payment link and give you a great discount Product Description Solar Power TPMS Car Tire Preure Alarm Monitor System Auto Security Alarm Systems Tyre Preure Temperature Warning Specifications and functions:-Solar power charging, don't need to charge by connecting car cigarette lighter-Colorful LCD Digital displaying, clear to show tire information-Rear-time monitoring preure & temperature of 4 tires-Low air preure/high temperature alarm-High Temperature / Leakage / Low Battery Alarm-Intelligent Shock Boot when car moving, don't need to turn on/off-Wirele connect by sensors, easy install-Freescale chip sensors and fit on almost 98% cars on marketExternal Sensor (Optional):-Easy to install, convenient to replace-Dust-Proof / Water-Proof / Anti-theft-Anti High Temperate and Cold-IP67 Protection / Waterproof-Working Temperature: -20-80 -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. Please turn on monitor before install sensor 1. Pre and hold on the power button to turn on monitor2. Install External or Built-in sensors one by one