Not only cheaper, but gets you bragging rights about having military nuclear explosion grade mains filtering.
http://www.ebay.co.uk/itm/High-Effi..._Consumer_Professional_RL&hash=item3f0b7772af
http://www.ebay.co.uk/itm/High-Effi..._Consumer_Professional_RL&hash=item3f0b7772af
