Aqua-Dynamic’s Grey Galvanized Steel Pipe Nipple provides reliable, long-lasting performance for all your projects. The 3/8″ x 4″ nipple has male threads on both ends, allowing hoses and fittings to be securely connected to circulate liquid or gas. The Class 40 rating indicates that the wall thickness has been standardized for maximum strength and longevity under pressure. Made of heavy-duty steel and galvanized to resist corrosion, this nipple is ideal for use with other galvanized iron pipes and fittings for a wide variety of applications.