Combine the tear, weather and puncture resistance of a courier envelope with the cushioning of a duraliner bubble lining. Each Xpak mailer is made from 100% polyethylene. The white outer surface is ideal for high-quality printing. Anti-static release liner, doesn't stick to item being inserted or extracted. High slip lining allows easier product insertion and extraction. Hot melt self seal closure is a tamper evident seal. Exterior film has gray lining on inside. This opaque material prevents see through.