Abstract: A nasal mask of the type for delivering gas for example to ease or assist the breathing process includes a shell and a cushion connected with the shell. The shell has a side wall and a retaining ring disposed inside the side wall. The side wall and the retaining ring define a gap extending around the shell. The cushion has a side wall with an outer peripheral edge portion including a tongue extending around the cushion. The tongue of the cushion is received in the gap in the shell to secure the cushion to the shell. Various straps assemblies and forehead adjusters for nasal masks are also shown.