A Quantity of 500 - Booklet 9x12 Envelopes are great for sending letters, documents, booklets, catalogs, magazines, brochures, pamphlets, and more. The envelopes measure 9-inches by 12-inches and open on the long, 12-inch side. They have a standard gum seal. The large side opening allows for insertion of slightly thicker or bulkier inserts. To use, insert your items, moisten the seal, and press to close. The envelopes are made with 28# - White Wove Paper. These envelopes are great for standard size documents measuring 8 ½ x 11-inches. Make sure to measure your insert before purchasing to ensure a perfect fit. You won?t need to bend, fold, or crease your documents before inserting. Packed and shipped by limited papers (TM)