Mercury - Speedometer 80 MPH / KPH SmartCraft Analog Gauge White Face 110 mm 79-8M0052878. Overview. The Mercury Speedometer (79-8M0052878) gives you clear, accurate speed readings in both miles per hour (MPH) and kilometers per hour (KPH). The white face, black numerals, and glass lens offer sharp visibility in any light, while the large 110 mm design makes it easy to read even at a glance. Built for SmartCraft-capable systems, this gauge ties into your engine data network for reliable, real-ti