Pet-Specific Water Purifier Includes main unit + filter cartridge! Removes water contaminants (12 items) and chlorine, and can remove 50-70% of calcium and magnesium, which are contributing factors to urinary stones. Uses an additive-free filter that does not use silver ions. I received this, but I haven't had a chance to use it, so I'm offering it to someone who has pets! The outer box has a few scratches, but it's new and unopened.