Yamaha PSRE253 61-Key Portable Keyboard Bundle with Knox Double X Stand, Knox Bench, Headphones and Yamaha Survivalkit (Includes Power Adapter and 2 Year Extended Warranty) 61 full-sized keys are great for learning and developing keyboard playing technique. Duo mode splits the keyboard into two halves, each with their own "middle C" for practicing with a partner. The Aux Line Input allows you to connect any music device with a headphone output. Accompaniment Styles add a "backing band" to your performances while you remain in complete control of chord changes and arrangements. Phrase Record allows you to quickly capture and playback a short performance or phrase.