Stadler-Viega's Pexcel Pureflow™ Water System offers two types of tubing that work with one fitting system. Flexible Pexcel tubing snakes through walls and around barriers. FostaPex, a composite pipe, holds its shape when a clean, straight look or form stability is required. The system is dry fit as is done with copper, then pressed together. Tested and listed by NSF, IAPMO and ICBO.