The tzero is a han-made electric sports car that was produced in limited numbers by the U.S. company AC Propulsion. The tzero is based on the Piontek Sportech kit car, which consists of a fiberglass body built over a reinforced steel space frame with double wishbone independent suspension and rack and pinion steering. AC Propulsion added the AC-150 drivetrain, a single-speed electric system with an overall gear ratio of 9:1. Launched in January 1997, only three prototypes were built and plans for commercial production were dropped in mid-2003. The name comes from t0, the mathematical symbol for a starting point in time.