DIGITEN Water Pressure Gauge Meter 0-1.0MPa 0-150psi 3/8" for Reverse Osmosis System Pump Pressure range:0-1.6MPa or 0-220PSI Stainless steel.Diameter of gauge:2" Pressure Gauge with fittings for quick connection to 3/8" (9.5mm) Water Pipe Pressure Gauge for Aquarium RO Reverse Osmosis System with 3/8 Come with connectors(1/4 thread female x 1/4 tube, and 1/4 x 3/8 x 3/8 Tee).