These are in use on the Isle of Man on the Manx interurban tramway in the UK . A historic American stile trolley line that is fully preserved and still operating. Photo taken by UK collector Gene Kingsley. The insulator is mounted on a Fred Locke porcelain pin base as well . Here is a close up of the marking ... WOW![id=305723963] This is the first confirmed sighting of Fred M.Locke line insulators in the UK. Fred advertised selling there but none have been found there till now except for broken pieces of multiparts in the concrete base of the Fessenden radio tower site.