Mercury - Tachometer Gauge 6K Engine Monitoring Black Face Black Bezel 79-8M6020025. OverviewThis 6,000-RPM tachometer gives you a steady, honest read on engine speed without feeling fussy or overdone. It reacts the way you expect when you roll into the throttle or hit a bit of chop-nothing jumpy or unpredictable. After a few minutes behind the wheel, it starts to feel like one of those gauges you don't think about much because it just behaves. It's a straightforward piece of gear meant for ever