Humphrey poppet diaphragm air pilot valves feature the exclusive double diaphragm design.  Available in a range of sizes from 1/2 NPT to 3/4 NPT.  The diaphragm poppet valves have no sliding seals to wear out and require no lubrication.  The self-cleaning poppets make this design ideal in applications where the air quality may not be perfect.  Several low pilot pressure types are available, 125,250,500,501,590, 42 and M42 series .