This voltmeter is 0.28 inch 3 digit high accuracy dual display, the display is bright and sharp. When measuring current, the measured line provides power supply. Don't need an isolated power supply. A good tool to monitor charging LI-ion batteries and electronics bench, etc. Features - ColorAssorted Color - Size: 4.80X2.90X2.20cm/1.89X1.14X0.86 inch. - Material: Plastic. - Measuring range: The voltage range is 0- , and the current range is 0-10A. - Clear color display: The multimeter can clearly display voltage and current at the same time. - Simple connection: The voltage ampere monitor gauge is powered by the circuit being measured, no need to connect extra power source. - This voltmeter ammeter has a handy connection and a wide application. For example, it can be applied to monitoring storage battery, DC adjustable power supply, or voltage and current changing state of other device. - With reverse connection protection. If the positive and negative poles are reversed, the display will not be burned out. Specification - Voltage measuring range: 0- . - Current measuring range: 0-10A. - Working voltage: DC 4-30V. - Voltage error: ±0.1%. - Current error: ±1%. - Refresh rate: About /time. - Working current: <20mAh. - Operation temperature: -10 degree centigrade-65 degree centigrade. - Display color: Red and blue. Package list: 10 x digital voltmeters