Webpage here. Dunno what the effect on muzzle blast might be, tho.
UPDATE: after some search, I found the patent (search by city and "recoil" rather than company name). Didn't have time to really look it and the drawings over, but the description suggested it worked by redirecting muzzle blast rearwards. That's the principle of most muzzle brakes. The problem is the tradeoff between reducing recoil and increasing the shooter's muzzle blast as heard. A very quick read even suggested it relied upon spring loaded trapdoors, which have been tried for a century and do not work, given the incredible pressures we are talking about. Again, that was on a very quick read of a technical document.