Shown here are the three known variations of the Fred M.Locke cable (catalogue design #5) produced from 1901-1904. This design first appeared in the 1902 catalogue though the first production actually dated from late 1901 . The units shown were produced in late 1901, early 1902 and late 1903. The first 1901 production run featured an applied crown design where the crown and the lower body of the insulator were produced in separate molds and joined together with clay slip. This applied crown characteristic continued briefly into early 1902 after the factory was rebuilt as well using new molds . In mid 1902 new two part split molds where employed to shorten manufacturing time and reduce labour cost. The insulator on the left is a result of this new process . It has a mold line extending from rim to rim over the crown . This is the most common variant of this insulator. The early version from 1901 with marking 6-2 and a date stamp on the other side of the skirt is quite rare with only three or four reported. A handful of early 1902 specimens like the the centre unit were found in the Victor factory dump . The unit on the right is scarce but not rare and a moderate number of marked and unmarked units of this type are known and were found in a variety of places . The basic design of the U-529a was soon copied by nearly every porcelain manufacturer and became one of the most popular and widely used porcelain designs for heavy high amperage DC and AC cable construction during the 20th century.