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. The bow measures approximately 4" across. The exposed stitching detail and a raw edge is signature Baby Bling! 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.