A myriad of changes were made throughout the vehicle beginning with the availability of hydraulic brakes and a folding fabric sunroof in 1950. The rear window of the VW Beetle evolved from a divided or split oval, to a singular oval. The change occurred between October 1952 and March 1953. Beetles built during this time were known as a Zwitter, or hybrid, as they used the split-window bodyshell with oval-model chrome trim, vent windows and dashboard.