Breakaway collar is a must. I had a cat die from a collar my sister put on her and it got caught under a fence, I was 10 at the time and have not forgotten about that incident. I'm hoping I can use some kind of elastic, I find that's the best.
Have you had any experience with these calming collars?
Rosie - 13
Callie and Tigger, brother and sister - 12
Akira - 2.5
Peanut - 2
Nikko and Spencer, brothers - 3 months