The Baby K’tan ACTIVE is made of a breathable hi-tech performance fabric that wicks away moisture and sweat， blocks over 90% of the sun’s harmful UVA and UVB rays， and provides a unique temperature control. - Ergonomic positioning for healthy infant development. - Evenly distributes weight across back and shoulders. - Double-loop design slips on like a t-shirt. Sizing Calculator:   Material: 100% Polyester Positions: 6 Positions， from birth and up Weight Limit: 8-35 lb. (consult pediatrician for preemies) Machine Washable: Yes Matching Sash Included: Yes