Features: This voltage meter is well sealed and designed waterproof, which can be immerge into water for long time and still work normally. It is also moisture-proof, oil-proof, dustproof and vibration-proof. The voltage meter uses 0.28inch 3-digit LED display, clear to read. There are only 2 wires, easy to connect; it supports reverse input protection, will not burn out. Widely used for kids' cars, electric bikes, motorcycles to monitor battery voltage, and many other voltage metering purpose. Specifications: Display Color: Red, Yellow, Green, Blue (Optional) Working Voltage Range: 3.50V~30.0V DC Metering Speed Rate: About 1S/time Metering Precision: 1%(±1digit) Operating Temperature: -10℃~+65℃ Operating Humidity: 10%~80%(no condensation) Operating Atmospheric Pressure: 80~106kPa Sunlight: No direct Sunlight Display Size: 0.28" Hole Spacing: 34mm/1.3in Hole Diameter: 3mm/0.1in Wiring Length: About 85mm/3.3in Item Size: 17.8*40*17.4mm/0.7*1.5*0.6in Wiring: Red(IN+), Black(IN-) Weight: 13g(approx.) Package Includes: 1 x Voltmeter 1、This voltage meter is well sealed and designed waterproof, which can be immerge into water for long time and still work normally 2、It is also moisture-proof, oil-proof, dustproof and vibration-proof 3、The voltage meter uses 0.28inch 3-digit LED display, clear to read 4、There are only 2 wires, easy to connect; it supports reverse input protection, will not burn out 5、Widely used for kids' cars, electric bikes, motorcycles to monitor battery voltage, and many other voltage metering purpose