if i remember correctly, when both xtant and mtx came under the mitek umbrella, mtx advertised some of their amps with 'xtant cooling technology'. perhaps not exactly the same, but it looks like a variation. neither look like some great innovative technology, but they both appear to be very good designs. ideally, they would be better if they output the hot air through a clear opening, instead of small holes or some covers that impede the output of hot air, done for the sake of cosmetics. harmon kardon's old school tc series amps had a great fan design. very similar to the these, with a big 'tunnel' of aluminum in the middle, and a fan mounted directly to the chassis to blow the hot air unobstructed towards the outside. i've seen plenty of bad fan designs on amps, though. ppi's power class series, and mtx's black gold series had horrible fan designs, to the point of being almost useless. hard to imagine what some of these designers were thinking, its not that difficult to design a good properly designed fan cooled system in an amp.