Excellent MaterialThe lens is made of high quality polycarbonate, which can filter and reduce the intensity of UV, UV400, infrared and visible light. Protect your pet's eyes from snow, UV rays, wind, dust and fog. Adjustable StrapWith adjustable strap. The adjustable range of the upper jaw strap is 22-40cm and the adjustable range of the lower jaw strap is 16-26cm. The strap is made of cotton-cotton elastic band, adjustable elastic cord, suitable for different head shapes. So your pets can wear the sunglasses comfortably and firmly. Good protection for outdoor activitiesThe dog glasses is a good protection for your pet when you do outdoor activities such as skiing, climbing, swimming with your pets etc. Inside of the sponge cushionThe sponge is padded around the glasses, the high-density sponge has a very breathable effect, and the thermal performance relieves eye strain or shaft pressure and the dog is normally not uncomfortable. Size ReferenceThese sunglasses are more suitable for medium-sized dogs. For example: Beagle, Shih Tzu, French Bulldog, Pug etc. You can refer to the buyer show on the detail page. However, due to the different size of each dog, we strongly recommend measuring your dog's head size (upper and lower jaw size) before purchasing to ensure it is suitable for your dog.