AKAI Professional LPK 25, USB Midi Keyboard, USB-MIDI controller works with almost any audio software, 25 Velocity-sensitive mini keys, Arpeggiator, Sustain button, Octave Up and Down and Tap Tempo buttons, Plug-and-play USB connection to Mac and PC without driver installation, Fits perfectly in a laptop bag or backpack, Four programmable memory banks, Software editor for Mac and PC included, Power supply via USB bus - no additional power cable required, Dimensions: 9.65 x 34.04 x 2.79 cm, Weight: 0.635 kg