Specifications and functions -Dynamically monitor tire preure, increase traffic safety. -USB Out charging 5.1V 1A fast phone charge -Colorful LCD Digital displaying, clear to show tire information -Rear-time monitoring preure & temperature of 4 tire -Low air preure/high temperature alarm -High Temperature / Leakage / Low Battery Alarm -Intelligent Shock Boot when car moving, dont need to turn on/off -Wirele connect by sensors, easy install -Build-in sensors and external sensors options, meets all your need -Freescale chip sensors and fit on almost 98% cars on market Internal Sensor ( Optional ) -Please install in by Profeional car center -More stable and accurate -Anti High Temperate and Cold -IP67 Protection / Waterproof -Working Temperature: -40-125 -Battery Life: 5 Years, non-replaceable External 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 Full Packaging ListHost*1, Sensors*4, 3M glue*1, Batteries*2, Installation tools*1,User Manual*1 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. External sensor installation 1. Prepare the corresponding sensors and anti-theft nuts for the tire 2. Rotate the hex nut clockwise 3. Install the sensor to the corresponding tire 4. Tighten the hex nut in reverse to ensure close contact with the sensor and check the installation position for air leakage with bubble water