●100% polyester, water resistant, lightweight, quick dry performance ●Crushable and packable ●3.5 inches high, brims measures 2.2 inches, 2 sizes available, 7 1/4 suitable for head circumference 22 1/2-22 3/4, 7 1/2 suitable for head circumference 23-23 1/2 ●with an adjustable drawstring at the back for comfy fit ●About water resistant: it is a synthetic fiber with no vents. The cloth is thin and floppy, wouldnt stand up to a downpour. But in a drizzle, or light rain it would do fine. And no need to worry about shrinkage