Size:S The calming dog eye mask is brand new. Material is mainly black nylon, which has Good shading effect, non-stick hair，durable，and resistance soiling. Advantage Elastic design at the mouth makes dogs confortable Slider design can adjust the mask size Buckle design makes dog easy to wear Size Map SizeS : mouth circumference 4.72"-7.09", neck circumference 7.09"-12.6" Size M : mouth circumference 5.51"-8.66", neck circumference 7.87"-17.32" Size L : mouth circumference 7.09"-10.24", neck circumference 10.24"-22.83" Size XL : mouth circumference 9.45"-12.6", neck circumference 12.6"-25.2". Attention • Please measure the size of your dog, and choose the best for him. • Dog is a member of your family, please don’t leave your dog when he wears the eye mask. • The calming eye mask should not be worn over a longer period of time, and it should not be used to punishing the dog. Our company specialized in pet supplies such as pet costumes, pet tools, pet toys, and so on. We want to give the best for you.