Thermoplastic quick coupling series 21KB with valve is designed for connecting a plastic hose with a conical seat, for hose 4 x 6 mm with thread M10 x 1 and for hoses made of PVDF and PE. The CHEM (FVX) version is a PVDF material version; according to the manufacturer's catalogue, the maximum working pressure at 20 °C is 8 bar for the PVDF version.