Ely's 3 Pack Ribbed Strap Undershirts Ivory Scallop JellyBeanz Kids Children's Under Dress Ylvi Natural Summer children's sleeveless cotton vest undershirt boys base I shaped 3 Pack breathable Cherry Print Baby Undershirts Ely's & Co.. Our children's underdress Ylvi is the little sister of our Under Dress Freya and together with our Children's Over Dress Ylva completes the outfit for inquisitive little adventurers. The untreated fabric made of pure cotton is not only comfortable to wear, but also robust enough to meet the special requirements of childlike adventurousness.