This is a fully functional box based on the companion cube from the Portal games. It is intended to be printed in white glazed ceramic material. If you wish, you can purchase ceramic paint pens (like the ones you can use to draw on mugs and such) and add colored detail to this model. Although I have not tested this model in any other materials, they should also print fine. Due to the nature of 3D printing, it is not possible to create a tight seal between the "plug" and the opening of the box. Therefore, the plug is intended to sit inside the hole, but will be a loose fit so it will fall out if the box is turned upside down.