The "Wiggy" is a simple, extremely durable line voltage indicator (tester). It has two test leads connected to a solenoid coil inside a molded plastic casing. A spring presses against the solenoid holding it down. To show the voltage, an indicator bar is attached to the solenoid. As the voltage increases, the solenoid moves against the spring. The user reads the voltage by comparing the position of the indicator with a fixed chart on the face of the tester. If it is reading AC current, a neon lamp in the face of the tester lights-up, the unit hums and vibrates. The voltage it shows is a general approximation, not an exact value. It's strength comes from its durability, ease of use and ability to show both AC and DC plus the polarity of the current through the Red/Black indicator lights. Its nickname came from the company that introduced it; the Wiggington Company.
"Do you have a Wiggy? I need to test for voltage."
Wiggins Meter or Wiggins Tester