Bubble mailers should not be confused with bubble wrap although both are types of product packaging. Bubble mailers are plastic bags which are made up of different layers of plastic. Between each layer, or sometimes there are two layers laid on top of each other to form the sides of the product packaging bag, is a bubble of air that cannot escape because it’s sealed within the layers. The air bubble serves as a protective cushion that shields the contents of the product packaging from any sudden impacts or movement that could shock the contents and damage these.
Bubble wrap packaging is different because the air is contained within tiny individual pockets in the product packaging itself instead of one continuous layer of air forming between the layers of the product packaging. Sometimes bubble wrap is one long sheet for wrapping stuff to prevent these things from moving around within the cardboard boxes, especially during shipment or delivery. You may have seen bubble wrap sheets wrapped around large items like vases and framed paintings. The reason bubble wrap packaging is used for such large objects is because these cannot fit within bubble mailers.