... openings Personalized customer service Custom made picture frames and mat 1. Matboard (matboard, pre-cut mat board, mount board, bulk Mats,card board ... )2. White core, black core,c ream core 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 ...