We have a large, beautiful black and tan GSD. He is warm, loyal, loves all kids, protective (of course) and very very strong. We are training him in a different way.
He gets excited when he goes out walking or playing in the park. We really needed something that would HOLD him back when necessary, gently train but not CHOKE. This fits the bill. He didn't understand it at first but immediately he got it. It is easy to make comfortable and it seems to fit as well as some of the $100 or more harnesses. This will likely last a few years, maybe not a decade but it is of pretty good quality. It makes our family outings with one of our pets more enjoyable and even helped him tone down his excitement WHEN THE HARNESS IS NOT ON. I was worried it would be too small but any regular large dog (Danes, Rots, Mastiffs, GSD's, Labs, etc) should be okay. Not sure a Tibetan Mastiff or St. Bernard or BARKLEY (from Sesame Street) would fit, though....good luck.