Pinit Backings for 9 x 12 Prints. 9 x 12". .0625" thick E-flute Corrugated Cardboard.White two sides. Short-term Storage. SKU: K912625 (0)No Reviews yet Add to Shopping Cart Details It is a popular choice for a backing board because it is thin, rigid and economical. Details Back DetailsIt is a popular choice for a backing board because it is thin, rigid and economical. Reviews 0 Back Ratings & ReviewsNo reviews availableBe the first to Write a Review