Fit my rottie mix well and is strong and secure enough to hold up to her pulling (clipped in front). Once she was walking easily, I could clip from the top. The padding on the 40mm wide one is great, although over time it can flap over and not stay in place. I'm back buying new pieces to fit my new Belgian malinois, who is very strong and another puller on leash. I'm confident that this will stand up to her abuse and help me teach her to walk well. And if she suddenly bolts after something, this harness will help me keep her close.