Sorry Amanda, I do not know the measurements but it is for a small to medium dog. My snouser is 17 lbs and the collar was set on middle setting for him. He had it on for about an hour and we took it off because he didnt look like himself. Lol. Funny but true. I dont have a measuring utensil handy and wouldnt know what to measure. The vet clinic sold it to us as a medium. Hope this helps you, Tommy.