Mercury - SmartCraft SC1000 System Monitor Round Black Face 52 mm 79-879896K21. Overview. The Mercury SmartCraft SC1000 System Monitor (79-879896K21) is a compact, full-featured display that puts your engine's vital data right in front of you. Designed for front-mount installation, it fits a standard 52 mm (2-1/8") dash opening and includes a black bezel for a clean, factory look.. It delivers alarms for key functions like battery voltage, oil pressure, and water pressure, and depending on your