Need Help Plz! Device In My Car And I Dont Know What It Is?

[fatin]

I have this round black device on the windshield of my car in the upper left hand corner in the drivers side, and I have no idea what it is. It looks like it could be a tracking device but I really dont know and I need your help. I have taken a picture of it, and uploaded it. Please take a look at it and let me know if you have seen anything like it before. Thanks

https://mail.google.com/mail/?ui=2&ik=ef240e5710&view=att&th=129f72e414a9cdd6&attid=0.1&disp=inline&realattid=1341917485029567603-1&zw

[1990LS400]

I can't see your photo but the "device" may be a transponder for automatically paying tolls on toll roads and bridges. They are almost always mounted on the inside of the windshield but usually near the rear view mirror. Can you see any markings on the device?

[ClayShooter]

Your pic wouldn't load because of Google issues. Are you sure it's on the left side of the drivers side? If it's up near the rear view mirror, it's the rain sensor for your automatic wipers.