DIGITEN Water Pressure Gauge Meter 0-1.0MPa 0-150psi 1/4" for Reverse Osmosis System Pump Pressure range:0-1.0MPa or 0-150PSI Stainless steel.Diameter of gauge:2" Pressure Gauge with fittings for quick connection to 1/4" (6mm) Water Pipe Pressure Gauge for Aquarium RO Reverse Osmosis System with 1/4 Come with connectors(1/4 thread female x 1/4 tube, and 1/4 Tee).