This is a Kenwood VS-2 Voice Synthesizer module. The VS-2 is used to announce frequency, mode, and other information via the radio's speaker. It was removed from my TS-850 some years ago when the radio was sold to a friend who did not want any of the installed accessories. It was working correctly when removed, but I'm selling in the "for parts or not working" category with no returns because I do not have a radio to test it. It was carefully removed and stored since removal. NO visible damage, NO gunk or grime, NO odors. According to online references, this unit is compatible with TS850, TS450, TS690, and TS950 models.