Desk reference system contains a rugged plastic desk stand, 10 letter-size panel sleeves (20 viewing sides) with molded colored outer frames, and 10 snap-on tabs. Desk reference system can be expanded multiple times with Durable Sherpa Extension Modules (5698).

Extra-large, open-end expansion envelopes are specially designed to expand up to 1"" to accommodate bulky mailings. Center seam design provides extra strength for secure deliveries. 32 lb., natural Kraft stock prevents your private items from showing through. Envelopes are perfect for statements, invoices, small items and more.