K9 Optix dog sunglasses offer 100% UV protection and shatterproof lenses. Pink glasses have the rhinestone heart detail. Copper mirror glasses have a rhinestone paw print detail. Available in 5 sizes and 3 fantastic colors. Optix are designed for dogs with a wider nose bridge. Trying to stay cool this Summer? Our K9 Optix are so hot that they will make any canine companion look cool! So super stylish you might just want to keep them for yourself. They are the essential accessory for every fashionable canine! With 3 stylish designs, there's one for every occasion or outfit. Polycarbonate (shatterproof), 100% UV protection lenses. Metal frame. As seen in Disney's Beverly Hills Chihuahua. 2 adjustable elastic straps for comfort. Sizing Information: XX-Small: under 2 Pounds - Head Strap: 3-9" - Chin Strap: 2-3" - Breed example: Teacup Chihuahua, Teacup Yorkshire Terrier X-Small: 2-10 Pounds - Head Strap: 5-13" - Chin Strap: 3-7" - Breed example: Chihuahua, Pom Small: 9-25 Pounds - Head Strap: 12-20" - Chin Strap: 4-8" - Breed example: Beagle, Westie Medium: 20-60 Pounds - Head Strap: 15-25" - Chin Strap: 5-11" - Breed example: Dalmation, Border Collie Large: 50-100 Pounds - Head Strap: 18-30" - Chin Strap: 6-15" - Breed example: German Shepherd, Labrador Retriever * The chin strap is the length from under one ear (across the chin) to the other ear.