I have a Marathon Micromotor I have had for about 10years. Very quiet
and smooth. I also have 3 Flexshafts.
I ordered a cheap micromotor for a friend as a present, used for
manicure, dial for speed, foot pedal for on or off. Mine can be used
with dial for constant speed or foot pedal for variable speed.
You can order Marathon from Ebay, about $100. Mine was from local.
$400. Same unit.
My handpiece stopped working, company wanted to replace it for $200.
I took it apart, a permanent magnet that was glued in came loose.
Reglued, as I am a professional at gluing, year and a half still
Great for stone setting, so smooth running.
You will love it.