Waterproofing as needed for structural conditions: Our Schlüter-KERDI-DRAIN-DR collar can be ordered in different sizes depending on the waterproofing area associated with your point drainage system. The KERDI waterproofing collar made of polyethylene has a diameter of 17.5 cm. For even greater flexibility, the square collars can be placed in the centre of the assembly, while the rectangular collar also enable off-centre arrangements. The collar sizes corresponding to the standard sizes of shower areas.