The Optimum 6 Pack Bubble Mailer Size 4 (9.5 x 13) is lined with protective bubble wrap to help keep your mailed items safe and whole. The lightweight design of this cushioned mailer reduces the amount you need to spend on postage, so that you can send more for less. This product comes in a 6-pack for your convenience. This envelope has a self-sealing closure. Dimensions are 9.5 inches by 13 inches.