This item advertised it was reversible. However, the bottom piece only had pre-drilled holes for the middle wall to be on the right side. If I were to reverse just the outter door it would have entered into the big room with the litter box without the "entry space". I was very disappointed as I set this up so that my dog would stay out of the litter box. It would not have been useful to have the door open straight to the litter box. If I had wanted that I would have purchased a cheaper one that didn't have the extra space. If it is reversible make it reversible.