I just got one of these products for my 7 month old pup who a month ago weighed in at 30kgs, needless to say its struggle when he pulls and tried to say hello. I bougth the halti and on our first ever walk he managed to slip out of it several times so i went out and bought the Gentle leader, well what can I say, so much better. Its much better made and stronger and he cant slip out of it either, I definitely recommend to any eprsistant pullers