Face mask inner portion - has cylindrical connection piece located by peg inside rim of inner resilient skin

摘要

The breathing mask has an inner mask with a resilient shaped part (1) terminating in circular rim (3) which is stretched over a cylindrical connection piece (2). This rim has a groove around the interior and the circular part of the connection piece which fits inside the rim, has a peg (4) at the top. This peg then locates in a hole (6) made in the top of the rim, in line with the groove. Thus the connection piece is aligned correctly inside the rim.