The anti-collision ring can adjust in height and position. S = ring diameter 22CM (suitable for 4-10KG), neck circumference 28-40CM, chest circumference 32-45CM; M = ring diameter 33CM (suitable for 13-20KG), neck circumference 32-45CM, chest circumference 36-50CM. High-Quality Materials: Blind dog harness is made of aluminum, SBR, and foam material, odorless, reusable, and durable for long-term use. Easy to Put On: This halo for blind dog attaches to a vest harness, allowing your pet to wear it comfortably. The blind dog harness guiding device is adjustable and secured with touch fasteners to ensure comfort as your dog adapts to limited vision. The pet ring is adjustable to fit your pet's size and is easy to wear. Suitable for small to medium cats and dogs, helping blind pets safely navigate and become familiar with their surroundings. Lightweight design does not interfere with daily activities such as sleeping or eating. The anti-collision ring is made of aluminum, SBR, and foam material, odorless, reusable, and built for durability. Protect Your Pet: The blind dog halo collar helps keep pets safe and mobile, preventing collisions with walls, furniture, and other obstacles, reducing the risk of painful bumps.