This picture perhaps illustrates that you can never take anything for granted. David Bethman delivered several of my eBay purchases to me at the Seattle show. One of the items found was the OTE marked piece on the left. After a quick look, I was thinking, ooops, got one of those already at home, but this morning, I realized the wire groove area is quite different. You can see this in the picture. What you can't see is the German manufacturers tri-delta logo on the tops, with the letters KWX in a small rectangular box below the tri-delta mark on both pieces. So we have 2 insulators manufactured by the same company, with the same markings, but with quite different shapes. An interesting side note to this is that I have just purchased another from a collector in Germany. I am now eager to compare it with these 2 pieces, and to check for additional differences. BTW, thanks Richard Wentzel for the heads-up on the 3rd OTE marked piece. Much appreciated.