Mercury - Voltmeter 8-18V Electrical System Monitoring White Face Chrome Bezel 79-8M6020021. OverviewThis 8-18V voltmeter gives you a clean, steady look at your electrical system without bouncing around when the boat rocks or hits a little chop. The needle settles smoothly, so dips or spikes stand out right away. Out on the water, it becomes one of those quick checks you make without thinking-glance, confirm, and keep going. It's a simple, reliable gauge that helps you stay ahead of electrical h