Pilot Cap with tie string. Comfortable and very healthy for babies to wear, day and night. Babies lose a lot of heat through their heads - especially since they usually lack a full head of hair! Keeping a baby's head warm is very important for their healthy development and comfort. Some Caps are 100% Wool, others are 97% Cotton/3% Lycra. See pull down menu for options. This cap can be warn alone or under a heavier hat when going outside. Wool is from Australia, cotton is free from any harmful substances, sewn in Denmark.