8 ply wool,( U.S light Worsted) has been used in the beanies illustrated, however any ply can be used so long as the width (diameter) of the crown and the length of the beanie are the correct measurements for the size required. You will need approximately 50 gms of yarn and extra for the stripes.
Video Tutorials are available on the various stitches used in the pattern. These stitches can only be viewed on the ravelry site prior to printing the pattern. Just click on the various stitches to view.