TPO (thermoplastic olefin) is sometimes referred to as TEO (thermoelastic olefin). These are just generic names for plastics with an olefin base. Olefin plastics are those waxy feeling plastics that tend to smear when sanded at high speed. They also tend to get "hairy " when you grind, or saw it. It is used more and more often in automotive applications. Many of the later model plastic bumper covers are made from TPO.