The Rexroth Z2S22B1-51/ (part number R900433037) is a direct-operated check valve designed in a sandwich plate configuration for vertical stacking assemblies. Belonging to component series 5X, this NG22 size valve conforms to ISO 4401-08 mounting patterns. Its primary function is to permit free flow in one direction (from B to B1) while reliably blocking flow in the opposite direction, specifically within channel B. This valve is essential for preventing reverse flow in hydraulic circuits, contributing to system safety and proper operation. It’s built for use with standard hydraulic fluids like mineral oils (HL, HLP).