Take a look at the piece on the right. Both of these are CD 115 Hemingray insulators, but I don't ever remember seeing one like the one on the right. It is a Hemi No 10 piece with sharp drips. The base width and height measurements match to the one on the left. However, there are several differences: the top of the dome is indented inwards on the right one rather than rounded upwards on the left, the diameter from side to side at the wire grooves is almost 2 3/8 inches for the one on the right and only 2 1/8 inches on the left piece, the wire ridges are thicker, and the upper wire groove on the right one is wider than its lower wire groove. Anyone else seen one like this? Let me know...thanks, John