All our Poly Bubble envelopes are 2. 5 mil high quality tough, puncture, tear, and water resistant and quality bubble provides extra protection during transit. Use 4 x 7 white bubble envelopes with labels or why not just write on them if you want to save time and cost. Each shipping envelopes #000 4x8 envelope mailer has a unique 2. 5 mil thickness. As the sender all you have to do is peel off the self seal strip on the opening lip and fold over to make a permanent seal. Poly bubble mailers are perfect for fragile items, brochures, catalogs, books, bulky material, gifts, presents, electronic media and both and eBay. High quality self sealing bubble mailer envelopes, lightweight, which saves on postage fees. Available in a wide range of sizes. Inner Dimensions: 4x7 inches Bubble Poly Bag Outside Dimension: 4x8 inches Bubble Poly Bag Color: Golden Poly Bag Type: #000 Bubble Mailer - Poly / Mailing Bag Seal Type: With Adhesive easy close strip Outside Width: 4 inches bubble envelopes Outside Length: 8 inches bubble envelopes Usable Width: 4 inches bubble envelopes Usable Length: 7 inches bubble envelopes Quantity: 500 Poly Bubble Envelopes