The caps with 3 sizes for 0-4 years old baby Size S , the cap circumference is about 46-48cm for 0-1 Years old baby . Size M , the cap circumference is about 48-50cm for 1-2 Years old baby . Size L , the cap circumference is about 50-52cm for 2-4 Years old baby . The cap with double layers , outside material is cotton knitted , inside material is warm soft fleece , very comfortable . China top brand caps ,high quality ,exquisite made , the best choose for your baby .