Quick-Change Couplers, Part B, and Adapters, Part F, with an easy-grip compression nut require no welding or epoxy to assemble your pneumatic conveying systems. All couplers and adapters with compression nuts are made of aluminum. They are designed for low-pressure conveying systems and field installation, for use with 0.065 tubing sizes ranging from 1 1/2 to 3 inches.