This headband is one size fits most and the size cannot be adjusted. The headband is sewn at a 6" diameter (12" circumference), keep in mind that measurement is before it stretches. This is the perfect size for soft nylon to fit a newborn and stretch comfortably as she grows into childhood. The bow measures approximately 4" across. This style is sewn in two pieces and can be taken apart for hand washing or to mix-and-match. The Classic Knot material is a soft nylon, produced to our specifications, in the USA. Each headband is hand sewn and tied by women in our local community. Due to the nature of small-batch production color and sizing can vary slightly.