You will get two picture mats cut for 20x30 pictures. They will fit into any 24x36 frames. The opening is cut to 29.5 x 19.5 to overlap a 20x30 picture. 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. The overlap also helps to mount pictures to the back. These mats are acid free and cut from 4 ply mat board