The happy mouth is actually not rubber, it's kind of a plastic. It's not quite as hard as metal but it's not nearly as soft as rubber. I find a lot of horses really like it! I would choose this bit for a lot of horses. If Blu has a medium mouth I'd say it's a great choice. I like rubber bits for horses who have very sensitive mouths or to start horses with. I also like the little middle roller piece. Some snaffles when they bend in half poke horses in the roof of their mouths (depending on the horse's mouth shape and certain snaffles), this third piece will keep it from doing that. The copper roller bit you have is a good bit too, esp if he likes to play with stuff in his mouth. If he doesn't really care you don't need the rollers.