Boys' Sleeveless Yellow Muscle Tops are Made of Cotton Material. It's a sleeveless kid's tank top that makes hands flexible to use, the designation of strap hanging around your baby shoulder gives the convenience of fixing, the strap not easy to slip when one is wearing it The Baby's Sleeveless Muscle Top High quality, super soft comfortable, and breathable. It Marked for extra comfort. Its cute yellow color print and classic striped tank vest make baby cuter. It’s Suitable for baby boys from 12 months to 6 years old.