The FH-1 "faderHost" is a USB MIDI Host in an 8HP Eurorack module, allowing you to directly connect a USB MIDI controller to your modular synthesizer.
Using a suitable connector box, "USB MIDI controller" here includes an iPad or plain old computer.
As well as simple direct control of the output CVs from MIDI CCs, the FH-1 also offers
• LFOs on each output
• Step sequencers
• Polyphonic MIDI/CV conversion
• and much more
The FH-1 can be expanded with the FHX-1 Output Expander, for a maximum of 64 outputs.