XS - Nasal Distance: 35cm/13.78", Bust: 38-62cm/14.96"-24.41".(Note: if the ring is too big, you can cut the blue foam to adjust it) The pet anti-collision ring can be adjusted to your pet size, it is designed with a breathable waistband for ease of use. Material: Aeronautical Aluminum, EVA Foaming, non-toxic and odorless, it is wear-resistant and durable. Suitable for blind dogs or poor vision due to glaucoma, cataracts, retinal diseases, trauma, and diabetes. Easy to wear and helps your dogs transition to become familiar with existing or new surroundings quickly so that builds pet's confidence. And it doesn't affect daily activities, such as sleep, eating and so on. How it works - when the halo hit a hard surface, it acts as a buffer to safeguard your dog's head, face and nose from contact and avoiding pain and accidents. They will learn to trust it as it redirects them from bumping into hard obstacles. Product information X-Small (Pack of 1)