Several years ago I tried out an electronic gizmo for setting the timing on a Harley motor but can't remember the name of it.

Basically, you screwed some kind of a sensor into the timing plug hole then connected the sensor to a control box. You then set the box to the proper timing degree you wanted, started the motor and adjusted the timing plate until a green light came on and the ignition timing was set.

Anybody know of such a tool?