| 摘要 |
<p>A flexible plastic strip is attached with one edge to the lower rim of the slot of a letter box. When mail is inserted, the strip is automatically folded over and guided into the box with its lower edge, indicating the presence of mail. The flap can be specifically shaped for easy folding and provided with a self-adhesive coating along one edge which can be protected by a thin foil to be removed before use.</p> |
