I bought these because they were <$3 for 10 springs. I should've used the $3 on a different toy. Both my cats were entirely uninterested in these springs, no matter what I did to try to interest them, including dunking them in the catnip container. I tossed them, I rolled them, I sprung them, I batted them... they just watched. Judging. Perhaps because these are the least-springy springs I've ever tried to spring. I'm honestly not sure what I thought my cats would do with them, except roll/bat them around. That's my fault. Hence the judgment from my cats. When one of my cats finally interacted with the spring (several minutes after drugging them with catnip) and started chewing and biting it, I realized just how small these springs are. I definitely thought they were a couple centimeters longer and at least a centimeter wider in diameter than they are. They really are on the small side, and seeing her chew on it immediately made me quite nervous. I began checking the spring to see how flexible or brittle the plastic is. It's pretty flexible but I still don't trust it enough to keep trying to get them to play with them, especially when they really aren't interested. I was going to toss them since they're $3 pieces of plastic, but I figured maybe I can find a use for them in making art... somehow. I recommend using the $3 you might spend on these, on a different toy. My cats' favorites seem to be plush toys stuffed with catnip.