The Pet's Talk Collar, large size, fits pet necks from 16 to 26 inches. Record the pet's name, address and your phone number. With a flip of the lid, all information is given to anyone who should find your lost pet. Much faster, simpler, and more cost effective than national locating services. Your message stays put, even if batteries are removed, until you chose to rerecord it. Pets Talk small-sized collar (sold separately) fits dog neck sizes from 11-1/2 to 16 inches.