Urban Boundaries Moisture Wicking Thermal Black Running Winter Skull Cap/Beanie for Men I HAVE A BIG HEAD WILL THIS BEANIE FIT ME? Yes, it will! If anything, this thermal beanie runs large. Lying flat, this beanie measures 11.50 edge to edge. We recommend this running hat for men or women with head dimensions of 21.50 or greater. See our size chart in alternate images for head dimension size ranges IS THIS SWEAT WICKING HEAD COVER STRETCHY? Yes, it is! Its made of 96 Polyester / 4% Spandex. You can wear this workout beanie with glasses, headphones, you name it. It is super comfortable and will stretch to fit almost all head sizes (up to a 26 diameter). Because of the fabric composition and its size, this run beanie does not hurt to wear. Buy this beanie with the confidence that youll be comfortable! DO YOU RECOMMEND THIS WINTER RUNNING HAT FOR WOMEN? If you are a woman with an average head size and an average amount of hair, this hat will fit you great. However, if your hair is cut short and/or you have a small head, this wont be the hat for you. If your head, including your hair, measures at least 21.50 in diameter, this running cap will fit you great. CAN I WEAR THIS WORKOUT BEANIE UNDER A HELMET? It depends on how tight your helmet currently fits. While this is a lightweight, relatively thin winter beanie, it is not paper thin. If your current helmet gives you a little room to maneuver, then yes. However, if your cycling / skiing helmet fits tight, then this winter running hat will not be a great option for you. HOW DO I WASH THIS THERMAL RUNNING BEANIE? Wash this winter skull cap in cold water and dry on delicate. The hat is made of 96% Polyester and 4% Spandex so shrinkage should be minimal.