Features: Dimensions: 40 x 25 x 23mm Cutting Size: 30x20mm Measure range: DC 2.7-30.0V Minimum input: DC 2.7V Maximum input: DC 30V Permissible Error: 1% (+ / - 1 digit) Display: three 0.40" LED digital tube Display Color: Blue Refresh rate: about 500mS Current consumption: about 5-20mA Operating temperature: -10 °c ~ 65 °c Voltmeter with epoxy potting, Full waterproof design, Oil Pollution Prevention, Moistureproof, Shockproof, Dust-proof With Reverse polarity protection Please Note: Do not need power supply, can measure 2.5-30V directly If the input voltage is below 3.5V, the display brightness dims If the input voltage is below 2.5V,measuring inaccurate or no display If measure 10V below, accurate to 0.01V,display x.xx If measure 10V or more,accurate to 0.1V,display xx.x Package Include: 1x Digital Voltmeter