Adjustable waist elastic at sizes 86/92-134/140. The pants might shrink by the maximum of 5%. Wash at 40 celsius.
The sizes are long-lasting and by choosing the size that is closest to your child´s height it might be a fair size, but at first you can fold the pant legs. The growth of a child has been considered in the size range, thus the leggings can be used for longer time even tough the child is growing.