A spring that can drive them crazy ...
Coated spring
Some cats don't really care about the springs and others are so crazy about them that they don't want any other toys anymore: it's hard to know if your cat likes them or not without testing. This model is however attractive in a slightly different and more secure way than the classic spring because it is more tight, wrapped in a flexible sheath finished with small pieces of felt and sprayed with catnip.
It makes no noise, is light: your cat will be able to play with day and night without disturbing you.
Random colors.