Euro Black 4" Speedometer 60MPH -GPS4" - Hole Size: 3.375" (85mm)A drop in replacement for your current speedometer to match your existing instrument dash.GPS information is gathered from an internal GPS antenna. No external antenna required. The GPS Speedometer uses a highly accurate 48 channel GPS receiver. Speed data is shown by an analog pointer. This pointer is driven by a digital stepper motor for increased accuracy and minimized pointer bounce during vessel operation. Euro Black Series features perimeter-lighted black dial with bold white graphics, black aluminum bezel, contoured white pointer, and flat glass lens. Deutsch Connectorized harness is intended to fit directly into today's dash harnesses with easy Plug and Play connectors.Studded harness is designed to fit into existing dash harnesses all ready installed. The studded speedometer connects directly to the battery and ground without the addition of a costly connector.