The module is a power source for Base box. At least one working PSU module is mandatory to operate. The module is hot-swappable and can be changed when the device is in operation. Base 24, Base 24 front, Base 36 have two slots for PSU modules. In order to achieve high availability, it is possible to double PSU modules and in the unlikely event of PSU failure the redundant PSU will take over the power supply without any outage. Change of module does not take more than 10 seconds and there are no tools required. The module has 3 fans the rotation speed of which can be modified or switched off completely. In case of high temperature only the fans will start automatically (to prevent damage of PSU).