Our dog loves / requests this collar to go on walks. This is pretty massive for him since he HATES his harness. We got this collar because we wanted piece of mind that he couldn't slip it (not that he tries, but he is reactive) and that we wouldn't choke him and it's been perfect. He outgrew his martingale from the shelter (it maxed out at around 17inches) and we weren't sure what size to get him, but the 17"-20" has been a perfect fit of not being too tight or too loose. Plus he looks very handsome in green!