This is an expanding file box (also known as a concertina file), which is designed for organized document storage and transport. Subject
Expanding File Box. It is designed as a monthly (quarterly) filing box, with files labeled by each month's name.
Key Features
Indexing: The interior dividers have pre-printed tabs for each month.
Capacity: High-capacity models can hold more than 1,400 sheets of paper.
Versatility: This box accommodates both letter-size (8.5" x 11") and legal-size (8.5" x 14") documents.
Security: It includes a protective flap and a latch closure (a twist-lock or snap) to keep contents secure during travel.