300 - #1 - 7.25x12 (Poly) Bubble Mailers Padded Envelopes 100.3 Our poly bubble mailers are unique, lightweight padded mailers made from a durable, moisture resistant, multi-layer blend of polyethylene film. The film is laminated to a resilient, cushioning bubble material for added protection. Durable and moisture-resistant, with exceptional puncture resistance, tear strength, and cushioning performance. The self-seal closure provides a reliable, tamper-evident seal to secure all enclosures. The opaque, bright white exterior film creates a crisp, professional image for your company.