Autometer Ultra Lite 66.7mm Short Sweep Electric 8 18 Volts Voltmeter Peanut Butter Milkshake. Keep tabs on the health and output of your vehicles electrical system safely and accurately. With a patented air core meter movement, this gauge operates with category defining accuracy anywhere from 8 18 volts on negative ground electrical systems. Installation is simple and it can keep you from being stranded on the side of the road. Installation Instructions Gauge kit includes bulb and socket assembly, red and green bulb covers, mounting hardware, and detailed instructions for installation 12 and 16 volt compatible, well suited with nearly every street car or race car electrical system Autometers Race Proven Air Core Electric Instruments Provide Quick And Accurate Readings