Fernco 6" Flexible Repair Coupling. It is made of specially formulated PVC compound that positively seals any sewer & drain connections. Stainless steel clamps are corrosion-resistant & rustproof. Fernco flexible couplings have found wide acceptance among sewer and plumbing contractors and municipalities because of their quality and ease of installation. Rated for above or below ground applications, Couplings are leak-proof. Used for all types of in-house and sewer connections.