You will get one Double picture mat cut for 12x16 pictures. They will fit into any 16x20 frames The opening is cut to 11.5 x 15.5 to overlap a 12x16 picture. The overlap also helps to mount pictures to the back These mats are acid free and cut from 4 ply mat board Photo May not represent proportions of opening and outside dimension. For color displaying purposes only Also Available in packs of (2) All of our matting is cut from high quality 4 ply acid free mat board. Each mat is precision cut with beveled edges that show off the beautiful white core of the mat board.