STV MT-X708 7-Band Parametric Car Equalizer. It is a car audio accessory used to fine-tune the sound quality by adjusting different frequency bands.
It is a 7-band equalizer with dual controls and a subwoofer output.
The adjustable frequency bands include 63Hz, 125Hz, 315Hz, 750Hz, 2.2KHz, 6KHz, and 12KHz.
The product is designed to provide more precise tone control than standard bass and treble controls on a car stereo.