5. Please measure your dog's chest measurement at the same place as the line. The recommended breast size will be 2 inches smaller than the product size on the label, which would provide space for adjustment. If your dog's chest is approaching maximum chest size, you can choose the next size. 4. The handle on the back can help better control the movement of dog and for attaching safety belt. 3. Two attachment points for extra control. This harness attaches in the normal back/neck area and also under the stomach. 2. Vibrant Color & nylon strip with 3M reflective improve visibility at night. Soft padded in chest and belly for comfortable. 1. Easy to adjust and put on. Four adjustable straps allow a custom fit for your dog.