Mercury – Water Pressure Gauge | Dual Scale | Black Face | 2-1/8" (52 mm) | 79-8M0052850Mercury Water Pressure Gauge Dual Scale Black Face 2 1 8" (52 mm) 79 8M0052850 Overview The Mercury Water Pressure Gauge (79 8M0052850) gives you a quick, accurate look at your engines cooling system performance. It features a dual scale face displaying pressure in both PSI and Bar, so you can read it easily in English or Metric units. With its black face, white markings, and glass lens, it fits right in with Mercurys OEM black face gauge family. It