This means that two power supplies are used. One supplies the motherboard and the other graphics cards or the like.
Socket for 24-pin ATX + Bridge
Connector: 24-pin ATX
The main line can choose 10cm or 20cm or 30cm, the branch line is 30cm
Color: Black (Cables & Connectors)
Wire gauge: High quality UL1007 18AWG
If you need othe length, there is no problem.