These #10 regular envelopes measure 4 1/8 by 9 1/2 inches and are made from 70-pound bright white paper. They are suitable for mailing checks, invoices, letterhead, personal letters, statements, and direct mail. The envelopes feature a moistenable strip on the inside of the back flap for secure sealing. They are designed for various personal and business uses, offering a reliable and cost-effective option.