Apollo MIDI over Bluetooth connects 2 devices with each other, either iOS or macOS. Hence my MIDI USB keyboard can now be connected with out any wires between Mac and iPad. The USB is plugged into the Mac, and Apollo transmits the MIDI over Bluetooth. Nice. Yet another successful link was just between AC Sabre on iPhone to ThumbJam on an iPad.

Apollo MIDI over Bluetooth for iOS | Apollo MIDI over Bluetooth for Mac