1.It is used to monitor the battery voltage. It has a reverse connection protection function, making the circuit will not burn out, it's waterproof and , safe and reliable to use. 2.This round panel voltmeter is easy to read, and the real time monitoring of battery voltage is convenient to know the status of electric quantity in time. 3.Made of pc, it is high-quality materials, it's . 4.The length of this product is 3.6cm, the width is 2.4cm and the height is 2.7cm. 5.It is suitable for motorcycles, automobiles, ships, all-terrain vehicles, campers, caravans, travel trailers, etc. Specification: Item Name: Voltmeter Temperature Meter Input Voltage: 12-24V Output Voltage: 5V Operating Temperature: -40 Degree Celsius to 80 Degree Celsius Aperture Color: Color Display Note: Due to different production batches, there may be slight differences in products. Colour:Black Material:Plastic Package Contents: 1x temperature voltmeter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.