YEAH!
That's the device I'm looking for! Now to see what shipping would be...
or how to find it locally (I'm in SE Mich).

Glad to help. Someone on the Piper mailing list has mentioned this device
before, but the groupthink has been that the JPI would be more accurate
than a cigarette-lighter voltmeter like this. Still, if one didn't have
another way to get a quick voltage reading, it's better than nothing.

Jack, I agree with your counsel and Jim's, that calibration may be an
issue. However, I've got a pretty good digital multimeter, and a REALLY
GOOD Hewlett Packard laboratory power supply that should allow me to
calibrate it (or create a deviation card) sufficient for my purposes.

Again, glad to help.

-Jack