I use them for 1 year, but I can say that the picture is not the sub Twin 18X! The real has 4 handles to carry it, the grid does not rise to the top and the yield is much higher.

The characteristics of the manual.

Features: Folded bass horn subwoofer
Freq resp: 35-150 Hz
Sensitivity: 103 dB
Continuous Power: 600
Music: 1200
Peak: 2400
Max SPL peak: 136 dB
Net Weight: 62.5 kg

The performance is there, and also the quality: it works very well, and much better than the copies.
Amplified by a Yamaha P5000S, it works well in low, but remains suppressed in 60hz (Blame it on the amp which has a switching power supply, if not with a real amp it goes down smoothly and becomes low physical ).
The crossover utility I was good because I had an amp that I dropped in the evening, the Yamaha has done all the Boulo thanks to the crossover.

The only negative is its weight ~ 65 kg but it is still acceptable, it is fairly compact and solid.