I've got a 9 month old, 51kg central asian shepherd puppy. He was pulling me everywhere until the canny collar turned up. Took a couple of days for him to get use to it, but now he is a totally different dog. Walks properly and only now and again does he try to pull. Even off the lead, I leave the canny coller on ant tuck the ends under his collar so he thinks it's still on. Wonderful. With a potential weight of over 120kg, and the size of a donkey, I just hope the canny collar will still fit. Thank you so much for a wonderful collar. Made extremely well and worth every penny.