TACHOMETER 4000 RPM, 110mm This is a genuine Mercury Marine factory OEM part, not aftermarket. Fits in 4-5/16" (110mm) hole. Bezels are sold separately from each instrument allowing for the boater to select the color of their choice to compliment or contrast with the face of the instrument. SC100 System Link gauges allow you to monitor vital engine and boat functions with digital accuracy. Furnished with a fog resistant lens, these gauges can be "daisy chain" interfaced between other SmartCraft products using a plug‑in connection. SC100 link gauges can be connected to a SC1000 System Tach, a MercMonitor or System Monitor.