I have a Yorkie who thinks she's a Lab (I have one of those too!) I have a the regular Chuckit for Lillie and the small one for Josie, the Yorkie and Ball Tyrant.  The Chuckits have saved my arm as I spend close to 2 hours a day outside with my fur babies.  The only improvement I would like to see would be rubber grips on the handles as if they get wet, they get slippery. Now, I just keep paper towels with me and wrap one of two around the handles. If you have dogs who are ball-crazy and you don't want to end up having surgery for a torn rotator cuff, these are essential!