Extended Definition external super-tweeter designed by Sony for the SS-M9ED loudspeaker and the launch of the SACD format.
The SS-TW100ED super-tweeter extends the frequency response beyond... 100Khz !
A glowing and very detailed review is available at Stereophile.com but I'll just add this : why was Sony always so quiet about its superlative gear outside Japan ?
This page only covers the SS-TW100ED super-tweeter ; please refer to the SS-M9ED post for the details of the technical description of the entire SS-M9ED loudspeaker.
The total production run should be of about 500 pairs (95% of which are in Japan).
These images come from the three "1" dedicated catalogs : worldwide english, german and japanese, all published between may and july 1999.
Real SS-TWs here.