Feature: Solar charging board & USB Charging,high charging efficiency and durable. TPMS ensures proper tire preure, which is neceary to ensure vehicle safety, handling, comfortable driving, and tire life. After installing the tire preure monitoring system, it will remind you of the tire condition of the car in advance, and the system can monitor the tire preure and temperature in real time. Build-in sensors and external sensors options, meets all your need. Colorful LCD Digital displaying, clear to show tire information. Rear-time monitoring preure & temperature of 4 tires. If abnormal tire preure and temperature are detected, the system will iue a real-time warning sound and light up the flashing icons on the screen to deal with problems in time to avoid traffic accidents. Button Function: Left Button:Long pre to power on/off,Short pre is Up/Previoufinction. M Button:Long pre the " M" button and enter the settingmode after hearing the bi sound . Short pre the " M " button is confirm fuction. Right Button:Short Pre is 'Down/Next",Long pre will back to main menu. Internal Sensor: Working preure: 0 - 50.75 psi / 0 - 3.5 bar- Preure accuracy: plus or minus 1.5 psi- Transmiion frequency: 433.92MHz- Working temperature: - 20 - 85 Deg.C- Storage temperature: -40 - 125 Deg.C- Working voltage: 2.0 - 3.6V- Waterproof grade: IP67- Battery: built-in CR2450 button- Battery life: 2 - 5 years External Sensor: Working preure: 0 - 50.75psi / 0 - 3.5 bar- Preure accuracy: +/- 1.5 psi- Operating frequency: 433.92MHz- Working voltage: 2.0 - 3.6V- Waterproof: IP67- Working temperature:-40 - 85 Deg.C- Storage temperature:-40 - 125 Deg.C- Battery: built-in CR1632 button- Battery life: 1-2 years (can replace battery) TPMS Receiver: Battery: built-in 400mAh Li-ion battery- Operating voltage: DC 5V- RF transmiion frequency: 433.92MHz- Preure unit: Psi/bar- Temperature unit: Deg.C / Deg.F- Operating temperature: -20 - 85 Deg.C- Storage temperature: -40 - 125 Deg.C Package Included 1 Set External sensors/ Internal sensors