CME Key Midi Controller (XKEY 25 Silver USB) Xtra Mobility: Ultra 3.6 mm slim edge, elegant aluminum frame, light and portable design Xtra Professional: 25 Standard-size keys, Professional velocity sensitivity, Polyphonic after touch, High Resolution Pitch Bend Xtra Compatibility: USB MIDI compliant with iPad, Android, tablet / phone, Microsoft Surface Pro, Mac and PC Xtra Usability: Perfect for mobile music creation, studio recording, and live performance