high quality self sealing mailers, 3 layer co-extruded polyethylene film. Material is waterproof, seal is not. Stated measurements do not include flap 1. 5 Inch. White outer surface And silver inner layer provides confidentiality. High-efficiency mailers are perfect for shipping a wide variety of non-fragile items. High strength seams allow over-stuffing Water tear and puncture dirt resistant. Pressure sensitive adhesive provides a high strength durable closure. Superior tear and puncture resistance.