The MOTU Ultralite MK3 Hybrid is MOTU's first FireWire and USB2 ‘Hybrid’ audio interface.

FireWire has long been recognised as a reliable, high-performance connectivity standard for professional audio interfaces like the UltraLite-mk3 Hybrid. Meanwhile, hi-speed USB2 has also developed into a widely adopted standard for connecting peripheral devices to personal computers.
To fully support both formats, the UltraLite-mk3 Hybrid audio interface is equipped with both a FireWire A (400 Mbit/sec) connector and a hi-speed USB2 (480 Mbit/sec) connector, and you can use either port to connect the UltraLite-mk3 Hybrid to your computer. This gives you maximum flexibility and compatibility with today’s ever-expanding universe of Mac and Windows computers.
If your computer has both FireWire and USB2, then it is your choice, and your decision may depend mostly on other peripherals you may also have, or bus power. FireWire provides enough power on the FireWire bus that the UltraLite-mk3 Hybrid can be powered solely by its FireWire connection to the computer. If you use USB2, you you'll need to use the DC power supply included with the UltraLite-mk3 Hybrid, as USB2 does not supply enough power by itself.
MOTU FireWire audio interfaces are fully compatible with FireWire 800-equipped Macs. All you need is a standard FireWire 400-to-800 cable (related product to the Ultralite MK Hybrid product page). Just plug in and go. The FireWire bus operates at 400 Mb/sec, providing the same high speed, low latency and rock solid reliability that MOTU FireWire interfaces are known for.
MOTU Ultralite MK3 Hybrid