Includes a 3" seal that protects stored files from dust and dirt and ensures a flat top for stable stacking. Maximum security box with string and button closure keeps contents secure, even if box is overturned. Up to 50% stronger than other string and button boxes for stacking without shelving. FastFold® quick and easy assembly. Reinforced plastic handles make it easy to pull box off shelving. Box Type: Storage; Material(s): Paper.