The opening size is 11.5"x15.5" for 12x16 print.
The backing is also 4-ply.
The re-sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap.
Our acid-free whitecore matboards are a 4-ply papermat that provide
the aesthetic and design benefits of a bright white bevel., Each sheet
of mat board has a richly colored front surface, a white core and a
white backing. It can be used for matting photos, art, and needlepoint.
Also great for crafts, backboards, signs, children's projects, and