timer arm造句

On the back of Flip-O-Potamus is a timer arm which is pulled counterclockwise to start the timer.
For reasons unknown, it did not activate the self-timer : the timer had a separate release button that became available when the self-timer arm was cocked.
The self-timer switch, placed where the previous-generation models had a mechanical self-timer arm, permitted the battery check / self-timer beep to be silenced.
It's difficult to find timer arm in a sentence. 用timer arm造句挺难的