SMAKN&reg; 0.56" Waterproof Digital Voltmeter DC 2.5-30V LED Auto Mini Volt Tester Panel Meter (RED) Range: DC 2.5-30V ( Can Measure Power Supply Directly ) Power Supply: DC 2.5-30V (with the input common-line) Display: Three 0.56 " Red LED digital tube Resolution: 1% +1 digit; Dimensions: 40x25x23mm;Cutting Size: 36x20mm Waterproof, Dust-proof, Shockproof, Suitable for electromobile and etc.