This "hatinator" does not require head measurements/specific sizing. A "hatinator" is a hybrid of a hat and a fascinator. Because of its shallow crown and its inability to stay secured on your head on its own, it is attached to a headband for security. For a detailed item description, please email us at info@thehatgirls.com.Due to the nature of our product and for sanitary purposes, we do not accept returns or exchanges. For free in-store pickup at our Louisville, Kentucky hat shop, please choose the "Pick Up In Store" option at check-out. Make sure to follow us on Instagram: @thehatgirls