The CD 342 comes in two variants : A rare early unmarked top version and the more well known marked units . It is thought that a small initial production run of a few hundred units of the CD 342 was made in late 1902 or early 1903 to make sales samples and test specimens of the Locke #25 . A small shipment of these was made to Southern California for a short test line that was used for testing insulators for the soon to be constructed 127 mile long Borel Transmission line . A few old stock insulators left over from this production run were later shipped to Colorado (about a year and a half later) for the famous Locke 25 line. These were mixed in with the more recent 1904-05 production embossed units commonly found (shattered into a million pieces) on the now famous to collectors line in Colorado . The major difference between the two tops besides the embossing is that a completely different inner mold tooling set was used for the older no name top causing it to have a much thicker skirt and massively thick dome glass compared the more often seen embossed CD 342 tops See next photo for a normal CD 342 top[id=538885013]