Yamaha PSR-A350 Portable Keyboard

The scale setting buttons allow you to create custom scale tuning by altering each of the 12 scale steps
You can change the scale settings at any time, even when you are playing
The scale tune memory function allows you to store four of your own scales and recall them instantly whenever you wish
The pitch bend wheel allows you to control pitch in real-time to add realistic expression to your playing
The advanced vocal/melody suppressor lowers the volume of vocals and melody lines in the original recordings, leaving that part open for you to play