Pneumatic Ratio Relay, Four Port Non Bleed Relay which Produces a Modulating Pressure Output, Proportional in a Fixed Ratio to Pilot Input Changes, 5 Psi Input for 3-13 Psi, Wall, Inline or Panel Mount, 0.002 Scfm Airflow Usage, Port 1 has 1/4" Barb Fitting , Other ports have 5/32" Barb Fittings, 0-140 Degree Temperature Range, 5-95% RH Operating Humidity Range, 30 Psi Maximum Operating Pressure, Adjustable 0-10 Psi Pilot Start Pressure, Includes Mounting Clip and Scaleplate with Psi Markings