PET stands for polyethylene terephthalate, a plastic resin and a form of polyester. Polyethylene terephthalate is a polymer that is formed by combining two monomers called modified ethylene glycol and purified terephthalic acid.

Plastic identification / recycling codes

When working with plastics there is often a need to identify which particular plastic material has been used for a given product. Most consumers recognize the types of plastics by the numerical coding system created by the society of the plastics industry in the late 1980s.
There are seven different types of plastic resins that are commonly used to package household products. The identification codes listed below can be found on the bottom of most plastic packaging.

#1- polyethylene terephthalate (PET)
soda & water containers, some waterproof packaging, tennis balls.
#2 - high-density polyethylene (PE)
milk, detergent & oil bottles. toys and plastic bags.
#3 - vinyl / polyvinyl chloride (PVC)
food wrap, vegetable oil bottles, blister packages.
#4 - low-density polyethylene
many plastic bags. shrink wrap, garment bags.
#5 - polypropylene
refrigerated containers, some bags, most bottle tops,
some carpets, some food wrap, chairs (back/seats).
#6 - polystyrene
throwaway utensils, meat packing, protective packing.
#7 - other. usually layered or mixed plastic.
no recycling potential - must be land filled.