The MS40 module is a no-keys model for an Accordion or Guitar Add-on MIDI Arranger. Keyboardists use these MS40s too, for instant backup band.
Especially when they don't have a MS50 MS60 or Ms100!
Keys are built in to those models.
All of these will import 3part accomp rythms as PATTERNS, about 8 to 12 at a time.
there are 1000's of styles converted from other arrangers too.
And it's also a great MIDI file player. Lead line removal offered.
very warm analog sounding instrument voices.