They are manufactured made from high strength polymers which are tear and weather-resistant. They come with a flap, which has a hot melt pressure sensitive adhesive strip for easy & permanent closure. Once sealed properly, it cannot be opened has to be torn.
Poly mailers are used by courier, parcel & e-commerce companies for the secure movement of their client’s documents and consignments.
They are light weight saving on freight and occupy very less space compared to paper alternatives.