The Casio CTK-900 is a lightweight, inexpensive portable arranger keyboard with 61 full-sized, touch-sensitive keys. The unit features a large library of onboard proprietary Zpi technology sounds, versatile auto-accompaniment options, digital effects, built-in speakers with amplification, a 6-track real-time sequencer for original composition or practice recording, and a large, backlit LCD screen for simplified navigation and control.