Chic and comfortable leggings, no elastic at the waist, but with a nice fit. They have pleats at the buttocks to flatter them. The model is wearing a size 3-5 years and she ordered the medium. They are therefore small. So take a size larger than usual.
 small = xsmall, 00 to 2 years
 medium = small, 3-4 years
 large = medium, 5-6 years
 xlarge = large 7-8 years