CAT Regulating Unloader Valves. Pressure sensitive feature permits wide range of flows. Handle allows for easy adjustment of system pressure. For single gun, non-weep applications. Small compact size. Color coded springs for valve identification. Designed to reduce pressure in the pumping system when trigger guns are used. Takes load off motor or engine when in bypass mode. All ports are 3/8" FPT rated to 195 Deg. F.