TPMS Tire Preure Alarm Monitor Solar Power Tyre Preure Monitoring System with 4 External Sensors Auto Alarm Security Notice: Please push left button over 3 minitus to turn on monitor, if it does not work, please try again after charging.When you receive the package and turn onthe receiver, the receiver displays "--" or "00", please don't worry.You only need to mount the sensor on the tire, wait for about 1 minute, and you will see the display shows the preure and temperature of the tire.Features:1: Anti-theft nuts;Easy installation;2: High and low preure, leak alarm;3: Sensor accurate wirele transmiion;4: Environmental protection solar cells;5: LCD display screen, Simple user interface;6: Air leakage alarm, prevent tires from bursting;7: High accuracy, Using Freescale imported chips;8: Real-time monitoring tire preure and temperature;Specification:Display: LCD color screenSensor Battery life: 2 years (Replaceable)Packing size: 21 x 15 x 6cm (8.3 x 6 x 2.4 in)Package weight: 375gOperating Voltage: 3.7V-5VOperating temperature: -20--75Adapt to temperature: -30--80 RF Transmit frequency: 433.92MHz 50KHzRF Operating Current: -90dbmMaterial Type: Plastic+Solar energyPackage Contents1 x Display screen, 4 x Sensor;1 x English Instruction Manual, 1 x Plastic Cover;1 x USB Cable, 4 x Screw Ring, 1 x Plastic Ring.Match sensor(charging/vent):