200 10x13 RED Polymailers Poly Mailers Shipping Envelopes (200 Pieces) 200 10x13 RED UneekMailers Self Seal Poly Mailers Water, Tear and Puncture resistant. The silver inner layer provides confidentiality Pressure sensitive adhesive provides a high strength durable closure, water and dirt resistant High-efficiency mailers are perfect for shipping a wide variety of non-fragile items