Schluter® KERDI-DRAIN-F Drain Flange — Universal Replacement BodyThe KERDI DRAIN F is the drain flange body that makes the whole KERDI waterproofing system work at its most critical point: where the membrane meets the drain. The polypropylene flange has an integrated KERDI collar the waterproofing membrane bonds directly into it, creating a sealed connection between the floor membrane and the drain body. If you're replacing an existing drain, upgrading an old installation, or need a standalone flange before