Piloted Check Valve Hgl-1/4-QS-8 with Sealing Ring Ol, with Qs Push-In Fitting. Valve Function=Piloted Non-Return Function, Pneumatic Connection, Port 1=Qs-8, Pneumatic Connection, Port 2=G1/4, Type of Actuation=Pneumatic, Pilot Air Port 21=G1/8, Festo