Unembossed American telegraph insulator. Not exactly a common insulator to be sure of, while not the straight skirt type, this looks a lot like the small CD 105,just bigger and unembossed. These are listed in the 2007 priceguide but not as "American product" insulators like other unembossed AM's are so I really have no set idea what an accurate price would be for it. Book says $20-$30 but that is for NN Brookfield? Light blue aqua and embossed only with an X on the dome. I don't recall ever seeing many of these for sale. Damage is one small fleebite flakelet on the domeside which you're looking at, a tiny flakelet on the resting edge of the base and along the mouldline, there's a 2" annealing surface fracture that is micron thin, very shallow not going all the way thru the skirt and apparently caused from a small amber impurity inside the glass. Displays mint. More pix at your req. $30 + actual shipping.