I bought this light up collar for my dog Bentley in green size MEDIUM and it fit him perfectly. It has three different settings that are easy to change with a click of the button and the best part is it’s rechargeable! He loves it and it’s great for him to wear at night so I can see him. It’s comfy enough for him to wear all day. I’m excited it came in time for St.. Patty’s day! I’ll definitely be purchasing this in every color! Get yours today for 75% OFF using Bentley’s code: SMILE75