It NEW that sell them for horses (Derby House about £5.99) - personally use a cat slicker brush as mentioned above for 79p from local pet supplies and does exactly the same job (and lested longer than my mates NEW one)
Ours is brilliant, if you can't get one buy a dog grooming brush made of curved wire, exactly the same and they work wonderfully on sheepskin, returning them to like lambswool after washing.