1000 9x12 PURPLE Polymailers Poly Mailers Shipping Envelopes (1000 Pieces) 1000 9x12 PURPLE 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