The deck is 11" wide though obviously the prints can hang off the edge. The distance on the deck between the bottoms of the two angled walls, when adjusted to the widest distance, is 10" SO it makes sense that I've seen it referred to as a flattener for "up to 11x14 prints" For completeness' sake, the full length of the unit in the other dimension (how much table space it needs) is 14". And I think I have it sold (I have accepted an offer, and if they follow through then it is sold.)
Duncan