This is a “pitchable noise” generator, hand built into an Atari paddle controller. The trigger activates sound and the pitch is controlled by the large original knob.
A red LED lights with the sound. It can easily be connect to amps, effects, recording equipment, etc. At the end of the original cord is a 1/4″ plug and running from there is a wall adapter (US Style) for power.
This was built as numbered series of three.