I have a dilemma. I have 8 of these - various glaze colors. I was pretty certain they were an M-2875 from the Multipart Porcelain Insulators (second edition) by Elton Gish (a great reference, by the way!). Today, a friend had the third edition value guide and we were looking this up. It seems that the M-2875 has been deleted and assigned M-2841. My dilemma is that the profiles are different, the sizes different and there isn't an O-B listing for this one. I could use some advice.