SMAKN&reg; 0.4" Waterproof Monitor 12 Volt Battery Meter 2.5-30V DC Auto Gauge Small Digital Voltmeter Red LED Measure range: DC 3.0-30.0V Display: three 0.40" LED digital tube Display Color: RED Dimensions: 4.0CM x 2.5CM x 2.3CM1.57inch x 0.98inch x 0.91inch