... mat board acid free and any thickness. Various color and multi openings. Professional design,color and style. 1. A photo frmae and mat board (matboard ... 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 multiple frame7. 4*6", 5*7", 8*10", 11*14 ...