Use this tag for questions about PETG.

PET-G (or PETG) is obtained by doping PET (PolyEthylene Terephthalate) with glycol (hence the -G). PETG is a thermoplastic material with similar properties as ABS, difference is that it is more flexible and shrinks less than ABS. This means it is easier to print than ABS and preferred over ABS, especially in cases where a 3D printer does not have an enclosed build platform.

More details here.