If you need to have a collar on your cat, a breakaway buckle is a must. Breakaway collars are designed to stay on your cat, but will break apart if your cat gets stuck on an obstacle. This breakaway collar is adjustable not only in size but also in the breakaway weight load. This is great for growing young cats!
I think this adjustable breakaway buckle is a great idea. We keep collars on our two orange tabbies. Timmy and William are brothers and while we can tell who is who when looking at their faces, from any other angle they are very hard to tell apart. Timmy wears a blue collar and William wears an orange collar. We put collars on them when they were kittens, but the breakaway buckle was rated for a heavier cat, so I had to "adjust" the buckles by breaking them a bit. It worked for us at the time, and the same collars are still going strong, but if I had known about adjustable buckles on collars, like this one, I sure would have given them a try.