The UniCover Flex covers are a combination of SteelCrystal and SteelMat. They have crystal clear acetate on one side and slightly frosted acetate on the other side. You simply choose which you would prefer, for your front cover by flipping the cover over. Use the crystal side, (best for photos) for the front when the cover wont be handled a lot. Use the frosted or matte finish side for your front, (doesnt show dust or scratches) for trade shows and open houses where the presentations may get handled a lot. This size accommodates up to 20 sheets of 20lb paper.