A FredArray with the MCM tweeter installed. Total cost of the drivers using this tweeter is about $250 for the pair. Add another $150 for crossover parts, speaker terminals, wire, mdf, paint, etc, and a pair can be built for about $400. I never did care for this tweeter in the Bottlehead Straight 8 (too bright), but with the right crossover to eliminate a 4dB 4-7khz peak and a bit of tizziness above 8khz it becomes very engaging. This is the one that will stay in the FredArrays.