Whistle for imitating bird song, has spacer folded into two parts along axis constituted by its diameter for providing rigidity to whistle after pressing and for assembling spacer with whistle body and membrane
摘要
<p>The whistle has a membrane (3) and a whistle body (1) made of flexible material for permitting the whistle to be plated against palate without letting air flow between the palate and the body. A spacer (2) is folded into two parts along an axis constituted by a diameter of the spacer for providing rigidity to the whistle after pressing and for assembling the spacer with the body and membrane.</p>
