Features: Flutter sleeves. Scoop back. Fabric strap across the back for extra security. Snap buttons for easy access for diaper changes. Body: 95% cotton 5% spandex | sleeves: 55% bamboo 40% cotton 5% spandex. Sizing and fit: Leos run true to size. Please size up if your child is in between sizes, and expect a small amount of shrinkage when washed and dried.