I saw it demonstrated on qvc the other day. They said that there was no difference in the actual product other than the color for dogs or cats. They sell 2 different sizes though. One is 1.75" and the other is 3" long. I think it was the smaller one that had the different colors. Out of almost 500 reviews for both sizes over 94% would recommend it. If you want to read the reviews you can go to qvc.com and search for item numbers M15553 and M17191.