Description OPW DPC-2200A 2IN Double Wall Pipe Coupling - Stainless Steel Double-Wall Swivel Pipe Couplings are a proven coupling and fitting system designed exclusively for use with FlexWorks Piping. Double-Wall swivel couplings and fittings are of a double-wall design and are used to interconnect FlexWorks flexible piping. These UL/ULC-listed stainless steel couplings must be contained within containment sumps and not directly buried. This pipe connection system includes an internally expanded stainless steel coupling attached to the end of a FlexWorks pipe section. The swivel coupling has a smooth sealing face fitted with a Viton® ring gasket. Double-wall swivel couplings eliminate the need for cutting back the secondary jacket and rubber test boots. They have an integral interstitial access port for connector and test tubes. These double-wall couplings permit higher interstitial testing pressures and eliminate added parts and labor costs.