MUJI (Mujirushi Ryohin) MUJI Kids Classic Popular Socks Black Size 15-17 cm Set of 2. I wore these with UNIQLO leggings. They haven't been worn much, but there is some pilling from washing. Would these be good for spares or replacements? Please understand that these are used items. For reference: The heel design is made so they can be worn even as they grow. The yarn used has an effect to suppress sweat odor. There is a support function around the instep, making them less likely to slip off or shift. The toes, which are prone to wear and tear, are reinforced with extra yarn. There is a space inside the opening to write your child's name, and the size is also indicated, which is helpful when purchasing the next size up.