Bankers Box LIBERTY PLUS Heavy-Duty Storage Boxes, FastFold, String and Button, Letter, Case of 12 (11111) Includes a 3" seal that protects stored files from dust and dirt Maximum security box with string & button closure keeps contents secure, even when box is overturned Up to 50% stronger than other string & button boxes for stacking without shelving FastFold quick and easy assembly Reinforced plastic handle makes it easy to pull box off shelving