These plastic collars are not safe and are extremely uncomfortable for a cat to have to wear. One of our new cats had to have one of these awful collars cut off as it was far too tight for her. They are being sold as “flea collars” and they are quite toxic especially to young children.
We do not recommend any collars as they can cause injury or even death from strangulation. If you have to put a collar on your cat please only use the “quick release” type.