CTK-3500 Black. Casio’s CTK-3500 portable keyboard opens up a whole world of music with 61 full-size touch-sensitive keys, 400 high-quality Tones, and 100 built-in Rhythms, plus an additional 50 Dance Music Rhythms when using Dance Music Mode.The all-new Dance Music Mode lets you create and remix electronic dance music quickly and easily. Connect to your iOS or Android device to use the free “Chordana Play” app, which plays easily downloadable standard MIDI files and uses the CTK-3500’s display to show you how to play your favorite songs. A convenient USB port allows easy connection to a computer or mobile device, with no additional software or drivers needed.  Make music anywhere with battery power, or use the included AC adapter. Includes Pitch Bend Wheel. From the manufacturer Specifications: Number of Keys: 61 (Piano-style) Touch Response: 2 sensitivity levels, Off Polyphony (maximum): 48 Number of Built-in Tones [Sound Source]: 400 Dance Music Effect: Yes Number of Built-in Rhythms: 100 Number of Built-in Dance Music Rhythms: 50 Lesson Function: Lesson Lite, Scoring System, Voice Fingering Guide Speakers: 3.9″ x 2 Amplifiers: 2 W 2 W Dimensions: 37.2″ x 12.1″ x 3.6″ Casio CTK-3500 61-Key Touch Sensitive Portable Keyboard with Power Supply No matter who (or where) you are, Casio’s CTK-35000 portable keyboard opens up a whole world of music with 400 high-quality Tones, and 150 built-in Rhythms including the all-new Dance Music Mode. 61 full-size, touch-sensitive keys respond to your playing dynamics, and let you express yourself naturally. Whether you’re just starting out, or using batteries to write your next hit on a tour bus, the CTK-2550 delivers hundreds of Tones and Rhythms to jump-start your creativity. It’s a perfect introduction to music-making, and a great-sounding way to have fun. The CTK-3500 lets you make music anywhere with battery power, or use the included AC adapter With 400 Tones and 150 Rhythms, the CTK-3500 delivers a huge variety of musical exploration The CTK-3500’s all-new Dance Music Mode lets you create and remix electronic dance music quickly and easily Connect to your iOS or Android device to use the free Chordana Play app, which uses the CTK-3500’s display to show you how to play your favorite songs Practice Playing on the Smart Device Screen Another fun feature is the ability to take 3-step lessons on the smart device itself using the virtual keyboard that appears on the screen. You can confirm the chords, melody and finger timing visually on the screen, while also using the scoring function to help you master the song. The 50 built-in app songs and your downloaded MIDI file songs are all available for use in your lessons.