They combine several components in a single housing, including the fuse, voltage selector, and RFI/EMI protection, thus saving space and installation time, and ensuring the components are compatible with each other. Some also add another level of safety by making it necessary to remove the power cord before changing fuses or the voltage. Without the cord, there's no chance for accidents. Modules provide power from 6 to 20 A and up to 250 Vac. The medical version lacks Y capacitors to ground, so leakage current is 5 A rather than 0.4 mA. All modules also meet EU's RoHS mandates on hazardous materials.