This mine insulator was very recently found at the victor plant . It is a wet process mine insulator with a clearly Fred Locke era sandy brown glaze, the typical fetteld firing rest, etc...There is some debate about it's U-# as is does not quite match any others listed . My suspicion is this was produced experimentally for Ohio Brass in the late Fred Locke era(1903-04) when they were jobbing Locke insulators. Ohio Brass was a big provider of hardware for electric mine trolleys and had numerous other mine insulators made with there name on them by other manufacturers of dry process porcelain. Whole sections of the Locke catalog were duplicated in the Ohio Brass catalogs of this era even using the same drawings and photos. This insulator would be well suited to big DC feeder cables in a large mine that would power the mine trolley engines on account of it's unusually large conductor groove. .