One of these is available locally, supposed to be New Old Stock. Dude wants like $250 for it though. It seems to be an accessory for Honda trail bikes in the 60's. Made in USA. It looks like you would put two rear sprockets on, mount this little gizmo to your swing arm, and then you would have a cable actuated two speed. I might violate moped laws in most states, if cops had any idea what it was.
Know anything about these?