M-Audio Oxygen 25 25-Key USB MIDI Keyboard Controller Bus-powered 25-key USB MIDI controller - Ultra-mobile design 8 MIDI-assignable knobs - control DAW and virtual instrutment parameters DirectLink mode - instant controller mapping to DAW functions Dedicated ransport and track skect buttons - sreamlined session control Assignable slider - quick to Masster Volume. Pro Tools compatible - extends industry-standard functionality