CD 728.8 [010] (base embossed) BOSTON BOTTLE WORKS - OAKMAN'S PAT JULY 26 1870 -, threadless telegraph insulator, aqua color, interesting tapered slots in the pin hole. Displays mint but on the other side is a 1/2" upper wire groove bruise and a 1/2" x 3/8" base chip - Not bad for an insulator that is almost 150 years old. The book lists these for $1500-1750. Asking $1250 postpaid.