Thank you for you help
首輪(kubiwa) is the name of a regular collar (to restrain and identify).
What you have shown a picture of is a neck decoration, or 首飾り(kubikazari).
If you search for 猫の首飾り（neko no kubikazari) you'll find loads of results.
In the future, if you ask a question here, please try to show some prior research and your best attempt at a translation. Otherwise, your post will likely be flagged.