Need extra 3/8 inch polyethylene close tolerance tubing? Tubing is black opaque and doesnÔÇÖt let light through preventing algea growth. Rated up to 250psi. This tubing is used to connect the reservoir to the pump. You can also use it to connect the pump to a manifold before splitting off with the 1/4ÔÇØ tubing to individual nozzles