Retired lineman Bob Jackson says the pictures of these large porcelain multipart insulators were taken just before they were changed out for modern insulators. Bob described the location as being near Knight's Landing in California. Found on the line a wide variety of multi's...including M-4325's, M-3725's, M-4140's, M-4321B's, M-4382's and M-4415's. The line is mentioned in some detail in on pages 76 & 77 in Elton Gish's book, Multipart Porcelain Insulators. Installed around 1905, some of the insulators remained in service until just a few years ago.