I got this in small and adjusted it just u still a bit. I picked small on my review but fir some reason it had changed it to medium and im.not sure why.. I saw this collar and love the color and fun design and just loved it, I felt like it was Lucky. Lucky wears it under his shock collar it fits him perfectly. No improvement needed for this collar. It meets my expectations and more. I do reccomend to any dog owner because I love the colors and the fun doggie bone designs! The collar is adjustable so as he grows pr gains weight or loses c weight I can adjust the collar to fit him snugly. So far this collar has stayed exactly where it's a dusted and he has had it on a little over 2 months. I have room to extend as he gains weight and grows. The collar is soft the edges are not hard so it was comftorable on him right away even first day/night wearing it. Even now every once In a while I try to take a this collar off at night as I take his shock collar off but he does not like me taking it off at night so I don't. It looks great on him and it is soft and comfortable. Great fun design and color. He likes the co)ar and it's comftorable and soft on him and when I try to take off of him at night he dint want me to. It doesn't rub him or agitate him in anyway at all!! I 100% reccomend this to anyone who owns a dog of any size they make small medium and large who are all adjustable!