Yamaha PSR Series PSRS750 61-Key Portable Keyboard Powerful and hi-fidelity sound with increased speaker box size for full-sounding low end, Digital Amplifiers for great power efficiency and Digital EQ for precise tonal adjustment. FlashROM Expansion: A 64 MB FlashROM lets you install all new Voice and Style content. More great music-making content: 678 Voices, 322 Styles and 123 Multi Pad banks. Real Distortion effect: All-new guitar amplifier processing with effects. Audio Link Multi-Pad: Trigger WAV files on USB flash drives from the Multi-Pads.