Features: Solar or USB charging,much convenient and practical. Color LCD digital display for clear display of tire information Monitor the preure and temperature of 4 tires in real time 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 Internal sensors and external sensors options, meet all your needs Two units (PSI / Bar) changeable, you can set the one you like. Intelligent On and Off When the car is started, the vibration of the machine is automatically opened and the machine is shut down automatically when it is still, without manual operation. 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: minus 20 - plus 85 Deg.C Storage temperature: minus 40 - plus 125 Deg.C Internal sensor: Working preure: 0 - 51 psi / 0 - 3.5 bar Preure accuracy: plus or minus 1.5 psi Transmiion frequency: 433.92MHz Working temperature: minus 20 - plus 85 Deg.C Storage temperature: minus 40 - plus 125 Deg.C Working voltage: 2.0 - 3.6V Waterproof grade: IP67 Battery: built-in CR2450 button cell Battery life: 2 - 5 years External sensor: Working preure: 0 - 51 psi / 0 - 3.5 bar Preure accuracy: +/- 1.5 psi Operating frequency: 433.92MHz Working voltage: 2.0 - 3.6V Waterproof: IP67 Working temperature: minus 40 - plus 85 Deg.C Storage temperature: minus 40 - plus 125 Deg.C Battery: built-in CR1632 120mAh button cell Battery life: 1-2 years (can replace battery) Introduction of the button: Left Button: Long Pre to boot&shut down,Short pre is Previoufinction. Set button:Pre and hold the "Set" button to enter the settingmode after hearing the bi sound . Right Button:Short Pre is 'Down/Next",Long pre will back to main menu. Package included: 1 set x Car Tyre Preure Monitoring System