Amazon.com: Optimal Shop 24 Pin Main Second Dual PSU ATX Power Supply Motherboard Adapter Cable : Electronics
ATX - Wikipedia
Why is -12V needed on an ATX power supply - Super User
Amazon.com: Thsion 5 Pack 12V DC Input ATX Power Supply Connectors Cable - 5.5mm x 2.5mm DC Power Male Jack to 6pin Cable, for pico PSU and Power Adapter : Electronics