Schluter® KERDI-DRAIN-F FLANGE 2" ABS & PVCThe KERDI DRAIN F is Schluter's retrofit bonding flange designed to add KERDI waterproofing capability to an existing clamping ring drain without ripping it out. If you've got a standard 2" clamping ring drain (the kind that squeezes a vinyl liner between a flange and a ring), this adapter flange sits on top and gives you the fleece covered bonding surface you need for KERDI membrane integration. Works with both ABS and PVC clamping ring drains.