Mercury - SC1000 Speedometer 50 MPH SmartCraft Analog Gauge Black Face 85 mm 79-8M0135629. Overview. The Mercury SC1000 50 MPH Speedometer (79-8M0135629) delivers smooth, accurate speed readings with a bold, professional look. Featuring a black face with white numerals, a glass lens, and a standard 85 mm (3-3/8 in.) fit, this gauge combines classic style with SmartCraft precision. It's built to integrate directly with Mercury's SmartCraft network for dependable, real-time performance data - and