hourglass charger by joon bok from korea

HourGlass Charger

By overcharging cellphones keeping pluging after proper charging time,
huge energy and money is wasted.

This home appliance has glasshour-shaped metaphor and use recycled copper powder instead of sand.

While 1 hour, copper powder fall to bottom in keeping with energy conduction.
After 1 hour, electric cannot be conducted since all copper powder fell.

So people can save energy against overcharing.

And also after using 1 hour, user can turn upside down and use this charger more time.