100#2 Black Poly Bubble Mailers Envelopes Bags Extra Tuff Turtle Shell for Added Protection, Water Resistant Our poly bubble mailers are unique, lightweight padded mailers made from a durable, moisture resistant, multi-layer blend of polyethylene film. Self-Sealing (just peel-n-seal). keeps contents secure and tamper -evident and easy to use. The self-seal closure provides a reliable, tamper-evident seal to secure all enclosures, while being opaque, the exterior film creates a crisp, professional image for your company.