Duke is a sample library recorded from an old Magnus Chord Organ. The original instrument measures just few feet long and features compact mini-keys.
Besides the vanilla accordian-like organ patch, Duke comes with a fun extra called Duke Bass.
Duke is simple. The Kontakt interface has run-of-the-mill ADSR as well as a built in reverb control especially useful for live performance. And that's about it, UI wise! No need to fiddle endlessly with knobs - just enjoy the instrument.
Every Duke copy comes with multiple versions. Due to the limitations of some software, the neat UI is unfortunately only available in the Kontakt version. But you'll still get cool noises no matter what you play.