Features: 1. Automatic solar charging 2. Pressure/temperature detection and warning 3. Display and sound warning 4. (PSI/BAR) pressure unit selection 5. (Celsius/Fahrenheit) temperature unit selection 6. User can set tire pressure, Temperature alarm standard value 7. The monitor has a vibration wake-up function. 8. The display automatically turns on 9. With rechargeable battery 10. Supports up to 5 tires (spare tires) 11. The display shows the pressure or temperature of four tires at the same time 12. Emergency alarm for air leakage 13. Easy to install, stable performance specifications: Product name: Tire pressure monitoring system (solar TPMS) Voltage: 12V Working voltage: 5V Working frequency: 433.9200MHz Working current (quiescent current): 30uA Working temperature: -40~85 degrees Celsius Pressure detection range: 0~ 99 psi 0 ~ 5bar Battery life: 3 years for external sensor 5 years for internal sensor Charging: Solar Operating current (dynamic): 8mA Includes: 1x TPMS system 4x sensor 4x screw 1x wrench 1x manual 1x anti-slip sticker