Akai Professional MPK Mini MKII 25-Key USB Midi Controller with Akai Professional Project 50X Over-Ear Studio Monitor Headphones Compact keyboard controller easily fits backpack and studio production desk (12.4" long, 1.6 lbs) Powered by USB connection to computer, with free virtual-instrument download packages Crammed full of all the features you need to play and edit musical ideas 25-synth-action mini-keys, 8 velocity-sensitive rubber drum pads with two banks, and eight assignable control knobs Circumaural (closed-back) design for outstanding noise isolation 50mm dynamic transducer delivers deep, rich bass Wide range frequency response: 10Hz-30kHz Collapsible design for increased portability-includes leatherette travel pouch