ANC II actively eliminates far more noise across the frequency range than a passive product, even across the lower frequencies. We use inverse noise current to cancel out the noise in the mains signal. The way this works is comparable to the technology in noise-cancelling headphones.
The SupaNova also includes:
Our Wireless Purification System to significantly reduce power-line noise without audible or visible side-effects
A Ground/Earth connection diagnostic
Polarity detection to ensure correct polarity at all times
Over-voltage Surge Protection, an auto-detection and cut-off circuit to protect your equipment