25 18″ x 18″ Self-Seal Unlined White Poly Mailers Size may vary by 1/4″ on either side Free Shipping to any US address! Self-sealing (peel and seal) unlined poly courier mailing envelopes from BubbleFAST. Perfect lightweight shipping option for any item/s not requiring cushioning. This is the largest size that can be used for Softpack Cubic Shipping.   Unlined Poly Mailers are: Sturdy 2.5 Mil thick. Water Resistant.    Tear Resistant.     Tamper Resistant. USPS, UPS and Fed Ex approved for domestic and international shipping.    Extremely lightweight. Save $$ on shipping your products without compromising on protection. 100% recyclable. Thanks for shopping at Bubblefast Mark and Robin Le Vine