Throttle/check valve type Z2FS... is used to control main flow rate (or pilot flow rate) in one direction of flow and to allow free flow in the opposite direction. The valve may be designed as double version (twin version - valve function is realized in two ports A and B) or single version (valve function is realized in one port A or B). The valve is applied to vertical stack mounting (sandwich plate) - generally is fitted between a subplate and a directional valve of the same nominal size and in this case is used to limit main flow rate (to control the speed of a receiver movement).