Warmup DCM-PRO Waterproof Tape External Corner - 120mm x 120mmThe Warmup DCM-PRO External Corner is used where two walls meet, your flooring can be particularly vulnerable to leaks or water damage. The external corner provides added protection, with a waterproof barrier that can\'t be penetrated. Designed for use with all Warmup underfloor heating systems, you will need to use this external corner if yours is a wet room design, or a layout where splashes are likely. We also recommended internal corners and waterproof tape, for full protection and peace of mind.