NDS 548 Gray Plastic Mini Channel Drain Coupling The coupling, also known as a coupler, connects channel drain sections, tees, and elbows together. The Mini Channel Drain Coupling is made of polyvinyl chloride (PVC) treated with UV inhibitors. Mini Channels are part of the NDS Profile Channel series, and ideal for capturing light water flows from pool and spa areas, concrete and paver patios, tennis courts, walkways, and driveways. Hassle-free limited lifetime warranty guarantees the NDS product is free from defects—or we’ll replace it.