Material: Plastic; For dogs about over 15 lbs, not for mini pets ! Head elastic band minimum 240mm/9.45", max 410mm/16.14". Neck around 190-310mm/7.48-12.21" between the pet can be worn. The doggy glasses can windproof Anti-Fog, Dustproof, protection against UV/wind/water/debris/snow. UV protection and prevention are key to your pet's healthy eyes.