Utility harnass

I'm puzzled by my experience with these utility harnesses. I bought a medium for my dachshund, and it was perfect! It fits snugly and stays in place. Encouraged by this success, I purchased a large for my Afrikanis, but the results were disappointing. The medium was too small around her body, though the neck fit well. So, I opted for the large size, thinking the dimensions would be ideal. Unfortunately, it's far too loose around her neck, and the body fasteners inexplicably loosen during use, rendering it impractical. I discovered this flaw while in our yard when my Afrikanis effortlessly stood on her hind legs and backed out of the harness. It's alarming to think what could have happened if we were out in public. As she's still a puppy and not fully trained, this potential safety risk is unacceptable. I'm definitely going to purchase another brand