Volkswagen began subcontracting to the Westfalia-werke in Rhea-Wiedenbrück, or more typically Westfalia, to build the official Volkswagen Camper cars sold in the early 1950s through 2003. Many models and interesting options were available for these vehicles. Early Volkswagen Split Screen windshield Kombi models between 1950 and 1967 are highly sought after collector vehicles. Beginning in the 1968 model year Volkswagen introduced the bay window replacing the split screen style. Production of Volkswagen camping cars continued well into 2003 and was based on the popular Volkswagen Kombi or "bus" as it is often referred to. Many other coachbuilders such as Dormobile, ASI/Riviera, Danbury Motorcaravans, and VW Sun-Dial also built camping cars based on the Volkswagen bus.