Which cables do I need between a Mac, the isolator and an RME UFX III audio interface?

For an RME UFX III we recommend the 7055-D, not the 7055-C.

Cabling with the 7055-D:

• Mac to isolator: USB-C to USB-B 3.0 cable.
• Isolator to RME interface: USB-A 3.0 to USB-B 3.0 cable.

Keep both cables short and of good quality. We link to lab-tested cables for
each side on the product page.

The external power input is not needed for this setup. It is there for devices
that draw their power from the USB port.