PET is the acronym for a very neat and sophisticated plastic called Polyethylene Terephthalate. 

PET is sometimes called polyester and is produced from mono-ethylene glycol (MEG) and purified terephthalic acid (PTA), which is derived from crude oil and natural gas.
For economic and safety reasons, it’s the plastic used to make the most common dishes on the soft drinks market today: plastic bottles.

Successfully used in packaging for carbonated soft drinks, bottled water, milk, juice, sports and energy drinks, jars, punts, pipes and trays for foodstuffs, household bottles, personal care and pharmaceuticals, as well as sheets and packaging film, PET is the type of plastic labeled # 1 on the bottom of bottles and containers.