The product is a pack of 500 No 10 double window security envelopes with a gummed seal, suitable for business and office use. These rectangular envelopes are made of paper and weigh 6.81 pounds. The Staples brand ensures quality, with a self-seal closure type for added security. The envelopes measure #10 size (4-1/8 x 9-1/2″) and come with a double window for easy address access. Made in the United States, this pack of envelopes is ideal for packing and shipping needs.