The Happy Days bandana is made out of cotton knit and jersey knit material. It is reversible so you can choose which side you would like your fur baby to wear, just simply tie it in a knot! It comes in three sizes, small, medium, and large. Small will fit up to 13 inch neck size, medium will fit up to 17 inch neck size, and large will up to 21 inch neck size. If you are needing a larger size, please message us. If your fur baby is in between sizes, size up and you can simply fold it over if needed to make smaller.