Check the stock / Stapler

You have to waste one staple to check if there’s a staple in the stapler.

This concept helps the user know the status of staple in the stapler. You will know there is staple or not by appearance.
It will avoid the waste for checking or avoid the situation the user has to find supplement urgently.

There is a transparent part on the top of stapler. You could see there's a slide in red color inside the transparent part.
The slide would move forward when the staple is less and less.
When you see the transparent part is filled with the red color, it means staples run out and you will need the supplement.