Duck Brand Clear View Packing List Envelopes offer excellent packing list security and protection. These envelopes adhere firmly and securely and are opaque, self-sealing and waterproof. Duck Brand's aggressive adhesive prevents tampering. These 5.5 x 4.5 inches; envelopes are postal approved and available in a 500 count package. From wrapping, packing, shipping, labeling and bundling, Duck Brand offers a full line of packaging and mailing supplies and accessories for your packing, mailing or moving needs. Got a project? Get the Duck to do it.