Sorry, Pablo, and thanks, Joe!
That's the one, just 2,99€: http://www.ikea.com/es/es/catalog/produ ... #/10303285
The pressure is not too much, so it won't affect the embossing or the box.
Careful, not to mistake it with this RIBBA frame: http://www.ikea.com/es/es/catalog/products/50270787/
It's cheaper and similar but won't allow to leave room to put the whole deck inside, as you can't set the back on the bottom of the frame.