... free mat board 2,A lot of colors and multiple frames 3,Professional design and quality. 4,Economic Price. 1. A ... , white core, black core of mat board3. Lignin free and acid free4. Thickness: 0.5mm--3.0mm5. Bevel cut, ... reverse bevel cut, V-groove 6. Multi layers and multi openings7. 4*6", 5*7", 8*10", 11 ... *14", 27*31" and other sizes are available8. A variety of design, prints ...