The clue is in the name! As each harness comes in 3 parts you can mix and match to get the perfect fit. They are well made and look comfy with the fleece lining. They have clips on the neck piece if your dog prefers the harness not to go over their head. The customer service is great, you don't need to guess, just call or send them an email and they will help you choose the right pieces and send you options to try on. You send photos of doggo sporting the various size pieces and they help you to choose the perfect combination. I've just bought a second one as a spare as Spencer loves to paddle and sometimes gets it soaked, if we're on a day out I want her to have a nice dry one for the rest of the day.😊