| 摘要 |
PROBLEM TO BE SOLVED: To suitably fix a mouthpiece to a user's mouth. SOLUTION: A vestibile shield having predetermined height overlapped with the teeth and gum of a user when positioned to the vestibile of mouth of the user and having inner and outer surfaces, the air passing means extending from the outer surface of the vestibile shield to the inner surface thereof so as to enable air to pass through a mouthpiece 102 and the outer seal flap 100 for a mouth corresponding to the air passing means or vistibile shield and regulable to one of two forms are provided to the mouthpiece 102. In the first form among two forms, the flap 100 is not substantially engaged with a user's face when the mouthpiece is inserted in a user's mouth and, in the second form, the flap 100 is pressed to be substantially engaged with the user's face when the mouthpiece 102 is accurately positioned in the user's mouth. |
