Mercury - Speedometer 80 MPH / KPH SmartCraft Analog Gauge Black Face 110 mm 79-8M0052857. Overview. The Mercury Speedometer (79-8M0052857) gives you accurate, reliable speed readings in both miles per hour (MPH) and kilometers per hour (KPH). The black face, white numerals, and glass lens make it easy to read in all conditions, while the large 110 mm (4-3/8") size ensures excellent visibility on any dash. It integrates directly with SmartCraft systems for smooth, real-time data and pairs perfec