Casio WK-6600 Portable Arranger Keyboard – Battery Powered w/ MIDI Leave a Comment / Uncategorized / By Alexander / June 13, 2018 88 GEARANK 88 out of 100. Incorporating 225+ ratings and reviews. Street Price: $299.99 Manufacturer: Casio Features: 76 Piano-Style Keys Touch Sensitive Keybed 48-Voice Polyphony 700 Tones with Layer/Split and Effects Built-in 32-Channel Mixer Built-in 17-Track Sequencer