She was 12 years old when I adopted her from the shelter, and had been brought in terribly matted, so she had been shaved. The mats were too severe. As she grew her fur back, with my assortment of grooming aids, I really didn’t get much loose fur off her, and with the long tined comb, did get small clumps of knotted fur, and she also pulled those knots out. But she didn’t like being groomed, and I have the bite and scratch marks to show for it. Even at that, she immediately comes back to me purring away as I sought out bandages. But recently, I found that she developed thick mats close to the skin, which are a real problem to get out, without risking cutting her. I did manage to get some of them, but then decided to see how this deMatter would work. To my surprise, she was real accommodating, and the second picture is some of the fur I got off with only a few strokes that would not have been removed by other combs and brushes I have, and I have an assortment of grooming aids. The first picture is her in all her fluffiness. The real challenge will be if she will let me get the mats from her chest area, as there are some real tough ones there. But this deMatter is so simple to use, and goes through her thick fur so easily that I have hopes that she will allow me to get those mats out. Otherwise, it is to the vet and $25 per 15 minutes of grooming. It is easy to set the depth of the deMatter. In edit: One of my long haired cats get thick mats, but they are easy to comb out. I found that if one combs against the lay of the fur, grabbing the mat, it quickly removes the mat. Again, they are not tight to the skin. So I ruffle up her fur to raise the mats, comb against the lay of the fur, and they are removed quickly. A few mats gone, some petting, and then a few more and that way less first aid required for me.