Please choose the Size According to the Pet's Back Length, Chest and Neck Circumference. XS: Back Length 18cm, Chest 27cm, Neck Circumference 20cm S: Back Length 21cm, Chest 30cm, Neck Circumference 22cm M: Back Length 25cm, Chest 33cm, Neck Circumference 24cm L: Back Length 30cm, Chest 36cm, Neck Circumference 26cm XL: Back Length 35cm, Chest 39cm, Neck Circumference 28cm XXL: Back Length 40cm, Chest 42cm, Neck Circumference 30cm Comfy Material: The puppy sweater is made of high-quality acrylic yarn, stretchy and breathable, soft and comfortable, high-quality materials and the good knitted fabrics keep your furry friend warm and protect her in cold weather Heart Pattern Design: Classic knitted style and cute heart pattern are fashionable and charming, which make your pets a lovely and eye-catching look and makes this dog pullover sweater a perfect match for Christmas, Thanks giving, Valentine's Day and all holiday Wide Application: This dog heart sweater is suitable for your dogs and cats to wear on a variety of occasions, such as daily wearing, Christmas, Valentines' Day, wedding, pet birthday party, pet beauty contest, holiday, festival, and more; Also Also great gift for your friend with pets, it is a essential apparel for every pet wardrobe