Mercury – Gear Oil Pressure Gauge 600 PSI | Dual Scale | Black Face | 2-1/8" (52 mm) | 79-8M0069429Mercury Gear Oil Pressure Gauge 600 PSI Dual Scale Black Face 2 1 8" (52 mm) 79 8M0069429 Overview The Mercury Gear Oil Pressure Gauge (79 8M0069429) gives you a fast, accurate view of your gearcase pressure so you can spot problems early and protect your drivetrain. It reads up to 600 PSI, with a dual scale display showing both PSI and Bar, so you can monitor performance in your preferred units. The black face, bold white numerals, and glass lens