光能书签 / Light bookmarks

When we open the book, it will light. Dot light unit wil absorb light energy, thereby scattering out a red line, reminding us that the last reading position.
Closed the book, there is no light. The bookmark is automatically turned off.
Dot will move each time reading the book can manually adjust the position of
their own. So next time you open the last time will be able to quickly find the reading point, so keep reading.