NS male couplings allow connecting round SPIRAL 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. The air tightness level can be increased to class B by wrapping the joints with the TAL, TALK, MET, DUCT or TAPV sealing tape.
