NSL male couplings allow connecting SPIRAL round ducts or round plain ducts with inner joints. The piece is installed by pressing both ends into the ducts to be joined, up to the stop in the middle of the male coupling. Next, the male coupling needs to be fastened to both ducts with self-drilling screws or rivets. As a result of the double EPDM rubber gasket, the product meets requirements for air tightness class D according to EN 12237.
