The sizing was perfect for my kitty. I ordered a small for my 10m old and it adjusts down to her 8in neck perfectly. She wasn’t a fan of it at first and tried to kick it but it didn’t come off and her claws did zero damage. I didn’t make her wear it for the first two days after her spay surgery and I just kept an eye on her but now that she’s up and active it works perfectly. She seems comfortable and has taken to using it as a pillow. It lets her do anything she’d usually do but groom herself so it prevents her from picking at her stitches. I did order a cheap pack of breakaway collars a few weeks before the appointment so that she could adjust to having something around her neck but even without those I think she’d have been fine.