GSteg is correct. The CDT IES tweets have an attenuator between the x-over and the tweeters. When CDT originally rolled out the promotion in August, they only offered the TW-19S/LP or TW-19T/LP models. Now it appears they are offering four models:
TW-19S/LP (.75" silk dome)
TW-19T/LP (.75" titanium dome)
TW-25S/LP (1" silk dome)
TW-25T/LP (1" titanium dome) [SOLD OUT]
I would go with the 1" models if I had a choice. The titanium dome are brighter. The silk dome are smoother and might handle slightly less power (don't quote me on that). Show me comparable tweeters for $50. Not gonna happen. These are a bargain.