Digital Voltmeter Red Display 0.36 Inch 4.5-30VDC Module (2 Wire)

From the shop's description

Put a voltage meter anywhere with this very handy display. These are often used by RC hobbyists for keeping track of batteries but we thought it would be great on a breadboard or enclosure. This is the 2-wire version of the volt meter, two wires are used to power it and measure at the same time. Simply connect the red wire to the positive supply, and black to negative ground. The display has a microcontroller that will read the voltage, compare it to a stable reference, and display the voltage with 0.1V precision on a 3-digit 7-segment display. It works from 4.5V up to 30V so it will be good for nearly any electronic project! The meter draws 3-4mA to power the microcontroller and display. This particular LED display is a nice vivid green, which we found very readable. Mounting tabs make this module easy to attach to any box or plate. Technical Parameter: Measuring range: DC4.5-30V Power supply range: No need for additional power supply, directly use the voltage under test as the power supply, the range is the same as above Input (max.): DC30.0V Note: Input voltage higher than 30V may be damaged! Allowable error: ±1%; when the error is greater than or equal to 10V, the error is ±0.3V; when the error is less than 10V, the error is ±0.10 Working current: Red < 23mA Refresh rate: About 300mS once a time Display method: 0.36-inch Red 3-Digit Red LED display For use with positive voltages only! Lead wire length: 10cm Size: 23 x 15 x 10 mm, (without mounting ears); Length with mounting ears: 33mm Mounting holes: Pitch: 28mm