I bought a cute hat at the shop for my beloved cat's birthday, but she hated it and wouldn't wear it. I felt sorry for her trying to force it on, so this is for cats and dogs who are okay with wearing hats and clothes! Please note that the size is small! In terms of head size, I think it's about the size of an adult human's fist. Also, it's a slip-on type, so you can cut the part that touches the neck and adjust it with Velcro or something similar to make it fit. It's new, but I did try it on once, so please understand before you buy.