Product & specifications: Notes: Before placing an order, please measure the size of your dog's lower neck and chest to choose the right size. Refer to the size chart, please allow 1-3 cm differences due to manual measurement. When measuring the size of clothing for dogs, the proportion of the space occupied by the fur must be considered, not the measurement of the skin. Any questions, please feel frees to contact us Easy to Put on - This halo for blind dog comes attached to a vest harness so your pet can wear it easily. The blind dog harness guiding device is adjustable and secured by touch fasteners to ensure that your dog is comfortable as they learn to adapt to their poor vision. There is a rotary knob on the left and right sides of the bumper ring to extend the distance. Unscrew the rotary knob, stretch the iron wire to a suitable distance and then tighten it. Adjustable design - The pet ring is adjustable according to your pet's size, easy to wear.Suitable for small or medium cat and dog, allows your blind pets to quickly and safely become familiar with their surroundings. S-size is suitable for about 4-10kg pet. M-size is suitable for about 11-18kg pet. Material: Blind dog harness anti-collision ring is made of Aluminum, SBR, foam material, odorless, can be used repeatedly and durable for long time use. Lightweight, Blind pets collision ring does not affect daily activities, such as sleep, eating and so on. Protect your Pet, Reflective Design: Blind dog halocollar helps blind pet to stay safe and move freely, prevents it being hit in the street. And helps to prevent painful bumps from running into walls, furniture, and other obstacles. Reflective Design, high visibility, provides protection and safety in the daily walking. Specification: Material: Aluminium strip + SBR + foam size: S: Loop diameter 22CM (for 4-10KG) Collar 28-40CM, Bust 32-45CM; M: Loop diameter 33CM (for 13-20KG) Collar 32-45CM, Bust 36-50CM. second generation bumper rings can be adjusted front and back Weight: S: 350g, M: 450g