Quad Current Meter (QCM)
The Quad Current Meter is a tool for matching servos on giant scale aircraft flight surfaces. Any of us who have set up a GS plane know what a pain it can be to set up servos.
Listening for servo buzzing, using a volt meter to measure each servo, feeling linkages for binding. The most used method by far is the use of a Digital Volt Meter set and configured to measure amperage. Jumping from servo to servo and then back again as you make smaller and smaller adjustments.
Enter the QCM. With a single unit you can now plug in all 2, 3, or even 4 servos and measure their individual current on the same screen.
Above is a picture of QCM screen shots of a "4 servo group" of servos being manipulated with a QCM connected.