Fit & Design: Stretch-adjustable chinstrap for your size and comfort One size fits most for a comfortable look and feel Crushable, flat brim is travel friendly SunglassLock™ keeps your glasses in place Reflective details for visibility in low light Technology: bluesign® certified main body fabric and sweatband for water-repellence and moisture wicking UPF 50+ sun protection to keep your skin from harmful UV rays PFA-free durable water repellent finish to keep the elements away Additional Details: Crushable, easy to pack Hand wash cold, line dry. Do not bleach, iron or dry clean Hat circumference: Medium: 22" – 22.87"; Large: 22.87" – 23.87" Crushable brim circumference: 2.75" Weight: 2.7 oz.