Soundtracker Kit
item #MR-1001 by Elenco

This little robot uses an electret microphone as a sound sensor to detect sounds and obstacles. When it runs into something, it 'hears' it and will back up and go in a different direction. It will also shy away from loud sounds.

Year Released: ???
Original Price: $27

Technical Specifications:
Power Supply: 2 x AA batteries

Dimensions: 3½" tall x 4½" wide x 6" long
Weight: 6.3 ounces