Thanks for that Chris, it sounds as though these things work. I have to say i thought the price made it worth considering.
Roseanne, it somehow prevents limescale building up in appliances or whatever else the water goes into once it has passed over/through the device. It sounds like magnetising it alters the balance of the water so that there is less calcium but I may be wrong! I'm not sure I understand the principle. There may be more information on the website, there are certainly other products which look interesting.
If it works that will be great as I probably do at least 10 loads of washing a week, which means I spend about 15 pounds a month just on Calgon for the washing machine. I was talking to the girl who comes to cut hair and we were wondering if there was a descaler for hair as you would think that the calcium also left deposits on hair shafts and skin. She thinks it makes scalps more prone to itchyness, so maybe this magentic thing would be beneficial for skin/hair too.
I may just have to get one and find out.