The hat was crocheted using 8 ply Heirloom Colour Works wool, however, an equivalent 8 ply or DK should be suitable. For an extra loopy look, you can use 4 ply or fingering doubled, for this you will need twice the amount of yarn.
Sizing: Small/Medium and Large (Adult)

There are video tutorials on the various stitches worked attached to the pattern page, these can be viewed whilst the pattern is online prior to printing the pattern off.