This AXEON TF 1810 Membrane features a check valve to ensure maximum efficiency and performance for your TF 1810 system. With scientific expertise, it effectively removes impurities and provides clean, safe water. Trust in our domain knowledge to deliver quality results. (Actual product may differ from image) Features: TFC (Thin Film Composite) Membrane is for use with non-chlorinated water Individually vacuum tested and sanitized Integrated Permeate Check Valve