Bankers Box Heavy-duty File Box provides organized and secure, waterproof storage of letter-size and legal-size documents. Durable plastic (polypropylene) construction features reinforced corners for added strength so the file box can stack up to five high. Modular design of the TAA-compliant file box means easy stackability. Comfortable handles allow easy lifting. Locking lid ensures secure transport. Built-in hanging rail keeps files organized and accessible. Inside dimensions are 11-3/4" x 14-1/2" x 10-3/8".