All of our cats and dogs are collared, for the chance they get loose outside. They all have a message with our number:

Help Me
Find Home
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The ones on the cats stretch. One time, our Rosie was using the handle on the heater register to scratch and her collar became hooked. Her just pulling away, pulled it over her head, no harm done.

I think we got those at Petco. The pictures on their web site do not show enough detail.