The $1 EBow mod

[rfurtkamp]

There's a few, originals don't have an on-off switch (they sense the string and go or something), then a later with a switch, then the black 90s.

The black 90s has a substantially hotter output, which allegedly people didn't like.

Then there's the current version with the options.

I've had my black one rebuilt by the factory (dead switch) several times - just tell them you want to keep the old circuitry because you like it if you do.