"Keith McMillen: Batt-O-Meter - Effects Pedal Battery Tester"

"The First Battery Tester for Musicians, Batt-O-Meter lets you check batteries INSIDE effects boxes and guitars without having to remove them.

Note: Requires 9 volt battery, not included.

5-volt or 9-volt batteryPlug the gold-plated Power Probe into the 1/4' input on most instruments and effects pedals to test the life...