Product Information Solar Powered Charging and USB Powered.The tire pressure monitoring system is solar-powered, but this TPMS can also be charged through USB when the sun isn't shining. Alarm Types and User-Defined Values - The TPMS tire pressure monitoring system pressure and temperature alarm values can be set by the user themselves. The TPMS Sensor is tiny in size, light in weight, has high tire pressure detecting accuracy (error range of no more than 3 psi). The TPMS sensor is simple to install and survive hard situations. Switch Button And Power-Saving Mode - Tire Pressure Monitoring System has a power-saving mode and a switch button, which use less power and last longer. The Tire Pressure Monitoring System will go into sleep mode if it has been in a static state for more than 10 minutes. External Sensor (4 PCS) Easy to install(Installation without professional personnel) Stable & Accurate (Accurate data makes sense) IP67 Protection / Waterproof (Respond to various environments) Anti High Temperate and Cold(-40-125) Battery: replaceable (2 YearsLife) Internal Sensor (4 PCS) (Only Style-C) Professional personnel are required for installation (special tools must be used). Stable & Accurate (Accurate data makes sense) IP67 Protection / Waterproof (Respond to various environments) Anti High Temperate and Cold(-40-125) Battery: replaceable (2 YearsLife)