Vktech 5pcs V20D DC 2.5-30V Red LED Panel Meter Digital Voltmeter with Two-wire This RED DC Voltage Meter with 2.5-30v range. It is easy to read, install and use Self-powered version and supports Reverse polarity protection Measure Voltage: DC 2.5-30V two-wire access Display: Three digit 0.36" LED, red color Highest input:DC 30V (higher than 30v has the risk of burn up)