4 IN 1 GAUGE,WHT This is a genuine Mercury Marine factory OEM part, not aftermarket.Fits in 4-5/16" (110mm) hole.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.