Geberit Lip Seal for Flush Pipe (also known as a flush pipe seal or washer). This is a small but critical spare part used to create a watertight seal in the flush pipe connection of various Geberit concealed cisterns. 
Key Details and Compatibility
Product Type: A replacement lip seal made of durable nitrile rubber (NBR).
Dimensions: It has an internal diameter of 45mm and corresponds to a DN40 pipe size.
Compatibility: This seal is compatible with the flush pipe elbows found on a wide range of Geberit concealed cisterns and frames, including those in the Sigma, Kappa, and Omega ranges, as well as the UP320 and Delta UP100 models. It is used where the horizontal flush pipe connects to the cistern elbow.
Function: The seal is designed to prevent leaks from the connection point between the flush pipe and the cistern body.