11x25 Matting for Picture Frame Burnt Sienna with Cream Core and 7x21 Opening Size (B555MAT) MAT SIZE: This matting fits a 11x25 frame. (frame not included) OPENING SIZE: This mat fits a 7x21 photo / print. (Actual opening size is 6.5x20.5) Matting Material is Crescent Mat Board. Burnt Sienna Finish / Cream Core with White Backing (PH Neutral). This listing includes (1) Custom Cut Mat. (The size selected represents the OUTSIDE dimensions of the matting.)