Plastic #1, also known as polyethylene terephthalate (PET), is a type of plastic commonly used in the production of beverage containers such as water bottles, soda bottles, and juice containers. 

Quite often, when a plastic is rigid and see-through, it is PET. PET is sometimes opaque and coloured, but this is less common..

While most types of plastic are not actually recycled, PET bottles often are. It is worthwhile trying to recycle clear PET plastic bottles.