The db99, as the name implies, is a high efficiency speaker which the manufacturer specifies at 98 to 99 db, with 8 ohm nominal impedance. It is a 2.5 way speaker with a built in powered subwoofer. I am unaware of any similar 2.5 way speakers with such high sensitivity and impedance.
I own db99 SE’s. They are close to 20 years old but still perform like a champ. I use them with 300B amps. The Seas and Scanspeak drivers in the db99 are very similar, if not the same, to what was in a pair of Joseph Audio speakers 10-20 years ago. My db99’s also have custom midrange drivers and Hovland Musicaps. I suspect I would have a sick feeling in my stomach if I ever gave these up, but in case I have to, or just wanted to change, there are several horn, coaxial, and single driver speakers that I would be interested in.