Some of it depends on your budget. My pet wears a gold Cartier Love bracelet. This is NOT a cheap alternative. However, it is beautiful, like her, and she loves it. It screws on, making it impossible to remove without tools. Granted it is a standard screw, but the principle is that she can't remove it easily.

Not sure if this link will work, but here, http://www.cartier.us/#/show-me/jewe...-love-bracelet