Made of 95% bamboo 5% viscose this fabric is buttery soft, and extremely stretchy. Breathable, thermo regulating, hypoallergenic, and eczema friendly. Sustainable and eco friendly material. Last three times as long as traditional sleepers. Stretchy fabric that grows with your child. Cuffs can fold over feet and hands creating a footie PJ with mittens (no mitten/hand cuffs for 18-24 month size). Double zipper for middle of the night diaper changes. Snug fit in accordance to CPSC safety regulations.