Have you read this entire thread. From what I have read the one with the flat face plate, metal dome, & wavy line cone is the first that came with them. The one, and this is not confirmed, with the stepped face place & circular pattern cone was a replacement in the series. I call Infinity and they were no help. The 1st WTL fits the description by glorocks. None of this is verified, but an assumption. Anyway, since I had 2 different tweeters bodies, and both dead, I decided to find a matched pair to substitute. The RS tweeters fit the bill and sounded great, although I have never heard the original to make an educated comparison.