Delta was General Motors' compact front-wheel drive automobile and crossover SUV platform, a successor to the GM T platform; it also replaced GM J platform and the Z platform used by the Saturn S-Series. The platform debuted in the 2003 Saturn Ion. Vehicles of this platform generally carry the symbol "A" in the fourth digit of their VINs. The Volkswagen Jetta is said to have been the target for the design group. Delta uses an independent suspension in front and Twist beam type in the rear.