So I'm trying to decide where to put up the new Hybrid FasTrak transponder on my windshield, and am wondering what that collection of black dots is on the windshield behind the rearview mirror -- is it to cut glare behind the mirror? Some other type of function? Purely decorative? I'm finding if I mount the transponder on the far left/right of the window it doesn't always read when going through the toll plaza (I'm holding it to the windshield for now) so ideally I would like to install the velcro strips on top of the black dots right behind the mirror -- minimal impact to vision field. Thanks!
reduce glare. If you open your sun visor, the black dots take up the slack where the visors don't shade.
