It is a lamp. If it would be a microphone, it's attached too high.
Cool. An internal radio that can be 'crafted into' an armor. Not bad. Now with helmet slot we could have i.e. be able to craft a radio headset from radio and some other parts (simply a radio that could be used on the head slot instead of a hand slot). Then this radio could be attached to certain helmets or 'crafted into them' as an integral part or a removable addition.