INOVART Picture-It White Pre-Cut Art/Presentation Mat Frames - Fits Artwork 12" x 18" Paperboard surface is neutral ph Smooth, non-glare finish Mats can be decorated with oil and water-based artist paints, mediums, inks, watercolors, markers, pencisl crayon etc Board thickness is 18 ply Mats have straight cut, non-beveled edges