One Size fits most (neck circumference 30 ~ 42CM)* Wash your face clean. * Masks should be worn 30-50 minutes. (Sweat until they are worn). * Wash your skin again. (Put some skin tonic or lotion for better use). * Even washed or soaked with sweat,it will not affect the masks role. * This mask can washing with warm water,use a mild detergent,then dry naturally,but to minimize the number of times of washing,prolong the service life of this mask .