Thickness: 3.15 mil Sheen: Matte 25ct Pretty Packaging that's perfect for small business owners to ship their products in Style! Durable & Strong These premium quality mailers are waterproof, tear-proof, puncture-proof and are thicker (3.15mil) than most others on the market. Easy Peel & Seal Each mailer has a strong self adhesive strip that is tamper-proof and makes packing orders quick and easy. On Trend Make your products stand out from the competition and stay on brand with these beautiful designs. Our Premium Poly Mailers are opaque and keep your product inside protected and private. These are not padded, and should not be used to ship any fragile items.