For several years, I have been using Airborne Air Motion Ribbon tweeters and I love them.
So far, I have been using the Model RT-4001 unit that can be crossed over down to 2000 Hz using a 3rd Order filter configuration. It has a very smooth frequency response up to 27 KHz and its impedance curve is linear at around 3 ohms. In addition, it provides a very wide horizontal dispersion giving an outstanding sound image which exceeds that of most dome tweeters.
That brand of tweeters represents an excellent value for the asking price. Meniscus Audio and Solen are both selling those transducers.