The Johnson Controls G-2010-5 Air Pressure Gauge is a compact, precision-designed gauge featuring a 1-1/2" dial and a 0–30 PSI range for accurate air pressure monitoring. Built with a 1/8" center-back connection, it provides reliable readings in HVAC systems such as air compressors, pneumatic controls, air handlers, and ventilation equipment. https://www.partshnc.com/1-12-030-18centerback