Plastic bristle foam pigs are used for cleaning plastic pipes (PVC, fiberglass, HDPE) as well as internally coated steel pipe. The bristles are aggressive enough to clean most buildups, but not harmful to the pipe\'s integrity. Models are available in 2, 5 and 8 pound per cubic foot foam density. The pigs are constructed from an open-cell polyurethane foam with a durable polyurethane elastomer coating in criss-cross pattern and embedded with plastic bristle straps.