It should fit most small pee pads, but we'd recommend against using this for a place to pee only. There are so many other great uses than just a place to go pee-pee! Most animals, by nature, do not want to pee where they sleep or relax (and vice versa). So if they are trained only to use the Pop 'N Go ® Pets as a litter box, they may not want to relax in it. We do think it could be used along with pee pads when you are housing brand new puppies or kittens to keep them safe. Again, please refer to a professional trainer or licensed Vet for recommendations!