| 摘要 |
<p>The mask has a body (2) whose back edge (5) has an airtight joint (7). The ends of a strap (9) are fixed to the back edge of the body. A lateral part (3) joins the edge to the front edge (4) and is made in one piece with the flat front screen (6) to form a transparent shell. The lateral parts have two side surfaces (3.1) that are flat and its upper and lower surfaces (3.2) are also flat. Each side surface is at an obtuse angle of 105-110 deg to the front screen.</p> |
