This set is made out of matching yarn.  The slouch hat measures 18" around and stretches to 22".  The length is 11" for a nice slouch when pulled down in the back of the head.  
The scarf is 41" long and 6" wide.  There is a unique keyhole opening where one end of the scarf is pulled through the other end (see picture).  This allows the scarf to lay flat under a jacket or coat.
The yarn is acrylic for easy laundering.