tapered brim adhesive secure closure straps size xs = 19 1⁄4 inch head circumference and 2 3⁄4 inch crown height size s = 20 1⁄4 inch head circumference and 3 inch crown height size m = 21 1⁄4 inch head circumference and 3 1⁄4 inch crown height size l = 22 1⁄4 inch head circumference and 3 1⁄2 inch crown height