This item came from our Wollensak building in Rochester, NY. This odd shaped front surface mirror is in the shape of a T. The top of the T is 18.5mm long by 10mm wide. The bottom of the T is 13mm and tapers down to 9mm wide by 26mm long. It is 3mm thick. This is not made of glass, but looks to be made of graphite or some carbon based material.