Mercury - Oil Pressure Gauge L-H Engine Protection Monitoring Black Face Chrome Bezel 79-8M6020012. OverviewThis L-H oil-pressure gauge gives you a clear read on how the engine's oil system is holding up while you're out on the water. The needle moves in a calm, steady swing, so you're not mistaking boat movement for a real pressure change. It becomes one of those quick checks you make without thinking-look down, see where it's sitting, and keep running. Simple, useful, and easy to trust.. Key F