Made of LDPE co-extruded film, it is durable, moisture resistant, coextruded polyethylene, the pressure sensitive self-seal adhesive closure system is reliable, easy to use and tamper-evident. The silver inner layer provides content confidentiality and the white outer presents a clean image to your clients. Lightweight for saving postal charge Superior puncture resistance Resistant to water and dirt Outstanding tear strength Easy opening Hot-Melt Self-Seal Closure Customized size and design is welcomed.