20 Liquid/Vapor ACME Valves All products are Pre-Applied with sealant on the inlet thread. Vapor Equalization Valve: 66.1206 Upper back check valve and lower excess flow valve combined. Other Items: 31 Bulk Plant Relief Valves 21 Type 1 ACME Cylinder Valves with Overfill Prevention Device (OPD) 18 Service Valves for DOT Cylinders << Return to Items