Polyethylene terephthalate
[[File:Bag-in-ball technologie.jpg|thumb|Example of bag-in-ball technology]] One-way kegs, also known as [[disposable]] kegs or [[Polyethylene terephthalate|PET]] kegs, were invented in 1996. They are usually made of plastic. Some types have a [[cardboard]] outer [[packaging]], which makes them easier to stack and transport, and also protects the plastic container. Some may use either bag in ball or spear technology. Products like the Hybrid keg have a puncture resistant wall and are easy to disassemble after use. Circular by design, the top and bottom chimes can either be re-used or recycled.