the gentle lead is the same thing as a halti, in the basics, i started axle out when he was 2 1/2, and sheeba started at the same time. we don't know how old she is. tiny our pit bull, got started when she was 1, and all the puppies i've ever raised, or babysat from then on used them with minimum resistance. we had an amazing reaction from all our dogs, although it did take a lot of work to get them used to it, as they were already over 50lbs in weight and pretty set in their ways (besides the puppies). the only problem i ever had was if you get them too big they can slip it off of their noses, so you do have to be really careful when sizing.