Gain space in your billy by obtaining double height in the back of the shelf, with this module you can place your video games, books or mangas to be able to see the ones you have in the back, with two modules you will get the space of another shelf of the billy of 40 and with 4 you would fill one of 80. You have the possibility to put the shelf in two different positions depending on the height you want to gain.

I hope you like the design.