The material says(Its not english so i am not sure) 80%Cotone which Im assuming is cotton ,15% Poliammide umm polister maybe?lol and 5 % Elastomero ,no guess there.lol Hope this helps! For the size there is none So it must be one size fits all but I can tell you I wear a size 6 1/2 shoe and I wear them but they run small. It also has the words Made in China and Runner D what ever that means..I took a pic of the back of the package if you can tell anything from that.Sorry I know this is not much help but They are cute and fun to wear!I love them with my Flip Flops!