50 #4 9.5x14.5 POLY BUBBLE MAILERS PADDED ENVELOPES 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.