Chesapeake Black 2 Hourmeter DigitalPerimeter-lighted Black dial with stylish Blue and White graphics, polished stainless steel bezel, contoured White pointer and domed glass lens.Hourmeter operates by applying battery voltage across the gauges register motor to ground. The register increments increase when the key switch in on. Route power through a normally open Oil Pressure switch to count engine running hours. 2 - Hole Size 2.0625 53mm SpecificationsAnti-scratch glass lensPerimeter lighted b