I have seen those in the pet supply store. If I need to, when he gets older, I will.
Have you used this type of collar?
Prong collars are known as “power steering” for strong dogs. Labradors are famous for pulling their owners and some owners and their dogs really benefit from using such a collar. They aren’t as awful as they look - put one on your arm and jerk it and you’ll see it’s not agonizing.
That dog’s prong collar is far too low on his neck. Leerburg has an article that shows how to fit a prong collar on a dog correctly:
http://leerburg.com/fit-prong.htm