The Mead No.10 Envelopes Security Press-it Seal-it in white color are designed for everyday mailing with a security seal feature. These #10 envelopes (4-1/8″ x 9-1/2″) come in a pack of 45 and are made of paper material. The self-seal closure type ensures secure delivery of your important documents. The rectangular shape and standard packaging make it a convenient choice for business and industrial use.