Etekcity 500 pcs Premium PM1 6&rdquo; x 9&rdquo;6x9 Self-Sealing White Poly Mailers/Mailing Shipping Envelopes/Bags Pack of 500 6" x 9" poly mailing envelopes with water, tear and puncture resistant High-efficiency mailers are perfect for shipping a wide variety of non-fragile items The silver inner layer provides confidentiality Pressure sensitive adhesive provides a high strength durable closure, water and dirt resistant Thick poly material, durable yet with lightweight, saved you a bunch on shipping cost!