Safely store up to 1,700 photos 4 x 6 in size; two dividers split the box into quarters for organization 60 pt. barrier board box is acid-free, lignin-free and buffered to resist acid migration; passed P.A.T. (Photographic Activity Test) Shallow lid is easy to remove for fast access, and metal edges add strength and a sleek look Now includes 50 unbuffered envelopes (acid-free, lignin-free, pH of 8.0–8.5) designed for labeling and organization Museum quality - your family history deserves the same level of protection used by the world's leading cultural institutions