The CP valves with non-metallic rings and steels guides are the evolution of the C valves. The thermoplastic materials special chemical properties make them suitable for a wide range of gases, from inert to those with aggressive components and presence of impurities.

Amongst the available compounds the most used one is glass fibre filled Peek™ in alternative to other thermoplastic materials such as carbon fibre filled Peek™ which is more suitable at working also at high temperatures. Most suited for dry conditions CP valves are used with refinery and process gas. The ring type shutters make them especially suitable for high pressures.

The CPT series distinguishes itself for the use of thermoplastic caps protecting the spring by eliminating the metal contact between the spring and its housing cavity. Such spring protections may be in different configurations.