These bonnets are made of 100 % GOTS-certified cotton. They are available in four sizes, ranging from 3 months to 4 years. Because head sizes vary quite a bit, sizes are given in head circumference as well as age. If you are not sure of the size you should get, please measure your baby's head. Merle's bonnets are made in Germany.  The hats are imagined and designed in beautiful Leipzig and the fabric gets manufactured in a German factory with very high standards, they only produce GOTS-certified fabric, and fair working conditions. The fabric is then shipped back to Merle's headquarters where the bonnets are hand sewn! The design is knitted (not printed, see details in the pictures) and the bonnets are lined with the softest fleece. Fabric: 100% organi cotton