I purchased this harness so I can allow my cat to explore my backyard. My cat is only 9 months old so I had to use a clip on the collar strap to get it tight enough so she cannot slip out. Once she is full grown, I wont need the clip. Because she is still small, she occasionally slips one paw out of the harness, so she can never be left unattended. I live in a city where it is illegal to let cats roam free. This harness allows her to experience insects, weather, wildlife and the feel of grass under her paws.