Notice that no where on the site does it explain what the "1 year warranty and a 30 day money back guarantee" actually cover. It's likely only for breakage. The warranty is not explained either; is it pro-rated for use? That information should be available without having to contact the company.
Note too: It only claims to reduce shedding. Not stop it. How is that to be measured? My dog's shed varies from year to year and season to season.
Sometimes those magnetic devices can have results on people, because people believe in them and that's where the curative or whatever powers come from. Placebos do work sometimes. How is one to convince their dog to believe?
There's a sucker born every minute.
A fool and his money are soon parted.