To make production assembly quicker, some manufactures such as Chrysler, Fiat, Dodge, Ram, Jeep, Hyundai, Kia & Volkswagen have their window regulators and other components mounted onto an interior door panel (modular design). In some cases, the window regulators are integrated as part of the door panel. Most of the panels use a cable design regulator. These door panels can be either plastic or metal. The plastic integrated door panels have a shorter life span compared to the metal door panels.