Not mono but bridged. Just saying...
From their website:
"In bridged mono, the AHB2 can deliver over 518 watts into each of 4-Ohm speakers."
Yep, that's why I wouldn't buy the AHB2 because I can't afford $6,000 for two, and one would be rated 100 W 8 ohms, that doesn't seem enough headroom for comfort in my application.