How do I distinguish PET from other plastic bottles?

Virtually all plastic cola and sparkling mineral water bottles are made from PET. Usually the PET container is marked with an identification symbol in the form of three arrows making a triangular shape, a number 1 in the centre of the triangle and the acronym PET under the base of the triangle. The symbol can be found either printed on the label or moulded on the base or shoulder of the bottle.