The Hobbytronics USB-MIDI Host provides a self-contained unit which can pass MIDI signals from its 5-pin DIN MIDI In/Out ports to/from the USB host port. This means that devices like the Arturia Beatstep, which don't have MIDI in (and can therefore only sync to computers using USB) are capable on syncing, via the USB Host, to MIDI drum machines etc. This little unit is less than half the price of its nearest (admittedly more robust) commercial equivalent. But in the studio, you just need it to do a job, not withstand the rigours of the road. Hobbytronics support were also quick and helpful before purchase.