A seal and a respiraoty mask having a seal adapted for confronting engagement with a surface of a user to form an interface therewith. The seal includes a first portion defined by a gel substance. In one embodiment, the seal includes a selectively formable substance adapted to be molded from a first...http://www.google.com.tw/patents/US7870859?utm_source=gb-gplus-share專利 US7870859 - Patient contacting seal and mask using same
