...and if you read the specs from the manufacturers website, they also list 285, 300 and 345 in various places
Actually the older model had 300 mics. Currently Squarehead makes small 225 mic array, a medium 285 mic array and a large 345 mic array. The largest array has a diameter of 2.12m (about 7 feet) and the smallest 1.05m (about 3.5 feet). Audio zoom is available both realtime and in replay as all channels can be stored.
And yes, it does run on Linux (and Mac OS X)
Software Engineer @ Squarehead Technology