They are a 15" 2235H, 10" 2122H mid, 2416H 1 inch compression driver with a 2307 horn with the H94 lense and a 077/2405 slot. Clasic 4 way JBL monitor. Crossover at 290Hz, 1300hz and 10k. The crossover is the 3145 which was used in both the 4344/4345 monitors. They are very smooth and dynamic and can really surprise you. You wouldn't think a set-up like that could be as subtle and revealing as they are. They image real well and the octave to octave balance is just plain amazing right out of the box. Lot's of fun to listen too. Well worth the time to build.