Polyethylene terephthalate (PET) is a very strong, fairly stiff, and impact-resistant material. It has excellent water and moisture barrier properties, making it a widely used material for plastic bottles manufactured for the beverage industry. For 3D printing, it is a great colorless, crystal-clear printing material, but it's also available in limited clear colors. The popular brand is Taulman's T-Glase.
The average temperature for 3D extrusion should be around 212-230 degrees Celsius. It has very low shrinkage and prints well on acrylic, glass, and Kapton tape. A heated bed temperature of 60 degrees Celsius is helpful.
There isn't any odor or release of fumes when printing, but it should be used in a well-ventilated area.