Features: 100% brand new and high quality. Accurate display voltage, with short circuit protective function. The battery voltage is displayed so that the operating voltage is stable and normal. After the start of the normal voltage value in the 13.5-14.5V, if too high or too low is not good, need maintenance. Installation need to drill 3cm diameter of the hole, and then into the product into the hole, and then lock the screw fixing ring. Specifications: Display range: 12-24V Material: plastic Product size: about 3.7cm Thread size: 2.9cm Thickness: 1.5cm Waterproof grade: IP68 Color:blue, red, green Package included: 1 x Digital voltage meter Notes 1. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2. Due to personal measurement technique is different, there may be 1-3 cm error of the physical.Thank you