In Stock. 45 Day Lowest Price - 100% Satisfaction Guarantee. The Studiologic SL-990XP is a Master Controller keyboard that will allow you to control MIDI instruments, sound modules and accessories. The SL-990XP provides an 88-note keyboard with full-size weighted hammer action keys that give a true piano feel. The keyboard features pitch and mod wheels. Performance control is available using program and bank change, transpose, MIDI channel change and 100 user memory locations. The SL-990XP provides MIDI Out and a sustain pedal input.