NS Series Piloted discharge check valves for compressors up to 25 CFM combine a pilot valve, a discharge valve and a check valve into one part. They are used on compressed air systems to control other devices using a pneumatic signal. The pilot valve is factory set in a pressure range with a unload (cut-out) and load (cut-in) setting. We stock several models and sizes with the most common pressure settings. Sizes not listed are available on special order.