Flexi has the stop button in a very convenint place for you thumb. Some others have a button on the side, not as handy if you need to hold your dog in place, or pull it back fast. I use two whan I walk Cooper and Nina, I have velco on the sides matching if I need to use them in one hand for a short time.
Chuck, Cooper and Nina
Shelter dogs aren't broken. They've simply experienced more life than other dogs. If they were human, we would call them wise. They would be the ones with tales to tell and stories to write. Do not pity a shelter dog. Adopt one.