I call this a Hemingray No 41 because it really is the bottom part of a No. 40 with a Hemi-42 dome. And get a look at that embossing: not only does it have the 'Made In U.S.A.' line, which is rare for this insulator, but the M and I in Hemingray are essentially joined and make a raised area. It has sharp drips. Regular aqua color. It came from the old NPRR line in western Montana. Anyone familiar with this particular hybrid?