Palmer Gas Test Gauges are a high quality Painted Black Steel gauge with a 4 inch (100 mm) case. These specialty gauges are used to test plumbing installations for leaks, as a part of passing inspections required by building codes.
Each gauge is dual scale - PSI (outer scale, printed in black) and Inches of Mercury (inner scale, printed in blue). Equipped with set hand to easily detect leak off. Solid brass internal body, with hex body and Schrader air valve and internal overpressure protection.