Elastic size parameters: the wrist circumference is about 16 - 28 cm/ 6 - 11 inches, the upper circumference is about 22 - 34 cm/ 8.7 - 13.4 inches, and the total length of arm sleeves is about 37 - 50 cm/ 14.6 - 19.7 inches, one size fits most people.^ Practical summer accessories: these long cooling arm sleeves will protect your arms from UV radiation in summer, at the same time, prevent pulled muscles while doing outdoor activities.^ Cool and breathable: these unisex UV protection arm cover sleeves are made of ice silk, a kind of smooth, cool, breathable and anti-static fabric, soft, skin-friendly and comfortable to wear, which are necessary supplies for your life.^ Ideal for outdoor activities: these UV sun protection arm sleeves can be applied for both outdoor and indoor activities, especially practical for training, racing, cycling, fishing, driving, golfing, jogging, climbing and more.^ Package includes: there are 12 pieces of cooling arm sleeves in various colors and designs, which will enrich your wardrobe, and allow you to enjoy different outfits every day, or you can also share some of them with your friends and family.