Both of mine wear GL when I walk them together. I weigh 95lbs and together my two weigh about 130 so they must be under control. It depends on your dog as to how much time is needed. I used lciker training to get mine used to it. For a week I would ltouch it to their noses, click treat, praise. Then I would loop it around their nose several times a day, click, treat, praise. Finally I would put it on, snap it shut, remove it immenidately, click, treat, praise. Lastly, I put it on for them to wear. My girl Rita did great - no problems. My boy Munson thrashed around the den for about 15 minutes until he finally accepted it. Now they love them because they mean we are going for a walk! Best of luck, take it slow, and remember that no matter how slow you take it - some dogs just do not want to accept it. I ignored Munson until he was done thrashing and then we went on a walk. Good luck!