These sunglasses can prevent some little rock or something might hit the dog's eyes. Not only protect dogs' eyes from wind and sun in summer but also snowproof, anti-dust in winter. FEATURES Large Breed Head Elastic Straps: 8.5" -15"; Chin Elastic Straps: 7"-12" (No Tensile Measurement); Framebridge Perimeter: 12". Perfect for longe snout dogs like German Shepherd, Gree, Husky, Alaskan Malamute, Doberman, and Shepherd dog. Small Breed Head Elastic Straps: 5.9" -11.4"; Chin Elastic Straps: 4.7"-7.9" (No Tensile Measurement); Framebridge Perimeter: 9.25". HOW TO WEAR Dog goggles are made up of a soft TPE frame and 2 adjustable elastic straps. Lenses are ultraviolet rays resistant. Sunglass vents can send out vapor to your dogs.