MDR-20-24 Rail Panel Mount Power Supply, 24V dc Output Voltage. DIN Rail mounting systems enables quicker installation time as all devices are able to simply snap onto the metal rails. Power supplies can be easily organised on DIN Rails within enclosed wall boxes or in areas where there is limited space. Similar devices can be mounted next to each other reducing the amount of cabling required. Most power supplies are convection cooled so no cooling fans are needed.