PJ5 Opaque Poly Mailers each measure 415mm x 325mm with an opening along the longest edge for easier insertion when packing. Poly Mailers are used by many online retailers as they provide effective protection for clothes and conceal high value pre-boxed goods in the post while being extremely lightweight to keep postal costs low. Our Poly Mailers are of market leading quality, made from degradable super strong white polythene at an impressive thickness of 75 microns. Each bag has heat welded edges and a self adhesive closure to make a permanent, tamper proof seal. The polythene is specially designed and tested to be waterproof and tear and puncture resistant to ensure goods arrive in perfect condition.