Organize project files, important documents and keepsakes in standard three-ring binders with Three-Ring Expansion Envelopes. Made of durable polypropylene, they resist spills and tearing while protecting your letter-size documents. Three-hole punched envelopes are closed on three sides and expand to 1-1/4" to hold bulky items or more than 200 sheets of paper. Made of acid-free material for archival-quality storage, clear envelopes feature a hook-and-loop closure for secure storage.