JAM Paper Dark Red #10 Business Envelopes measure 4 1/8 x 9 1/2 inches in size and are made out of 28lb, high quality, acid free and archival paper. These envelopes feature a beautiful, elegant, and stunning dark red color that makes them great for both personal and professional mailing purposes. The size of these envelopes makes them ideal for 3-times-foled standard sized sheets of paper. Use them to send letters, documents, and more from your office or home! Each of these envelopes has a rectangular flap with a reliable gum closure to keep items secure in the mail. This complete carton includes a substantial total of 1000 envelopes!