an air packaging device includes two layers of thermoplastic films , which form a sealable space where air is filled after first and second steps of heat - sealing process . the sealable space includes a number of independent sealed air chambers and a main air passage channel . the main channel has an air inlet . each sealed air chamber is connected with the main channel by at least one one - way valve each including at least two layers of plastic films . at least two one - way valves are installed inside of the air chambers . this air packaging device increases the cushioning protection where the protection is most needed , but can reduce air chamber dimension at less important locations in order to reduce the volumetric size and , hence , reduce the shipping cost .