The keys are velocity-sensitive, which means that they will respond to how hard you hit them. The Oxygen 25 is USB powered. The eight MIDI-assignable knobs allow you to fine-tune your sound as you record. The dedicated transport and track select buttons help you to streamline your recording session, instead of having to look for the right button. The Oxygen 25's assignable slider allows you quick access to Master Volume. This keyboard differs from the higher cost Oxygen 49 in that the Oxygen 49 has forty-nine keys, as well as nine assignable sliders. The M-Audio Oxygen 25 is Pro Tools compatible.