Made for pets, mainly cats. Neck size is approximately 20cm. It's made with elastic, so it won't constrict the neck, but please discontinue use if your pet dislikes it or if it seems likely to cause an accident. This is handmade, so please understand. If you wish to purchase multiple items, I will combine them, so please let me know before you buy. Feel free to ask about size changes or other inquiries in the comments.