FESTO Pneumatic Valves Check valve 611027 - FESTO 193154, Festo produces the GRLZ-M5-QS-4-D check valve, known for its reliable and efficient one-way flow control. It features compact design attributes ideal for pneumatic systems, ensuring smooth operation under varying pressure conditions. Typically, it is used in automation systems, preventing backflow and maintaining consistent pressure. FESTO 193154 Check valve GRLZ-M5-QS-4-D 1pc