It's one size and it fits my very slim 6 year old very well, not too big and not too small, she hasn't worn them yet as she needs them for her solo performance but I've tried them on her and they fit well
SKINS Unisex Essentials MX Compression Calf Tight
49 Review
Girls Winter Fleece Lined Tights Girls' Clothing
46 Review
Jefferies Socks Little Seamless Organic Girls' Clothing
44 Review
Warm and Soft Wool Socks for Kids - Cute Animal Design, Thick Thermal Crew Socks for Children and Toddlers in Winter
43 Review