For this bag you will need Worsted Weight 100% Wool Yarn.
Suggested needles are US 10.5, 24" Circular and a set of US 10.5 Double Point Needles.
You will also need four Stitch Markers (one in a different color), scrap yarn for invisible cast on, and a Tapestry Needle.
Felting supplies include a zipper-type mesh laundry bag, laundry soap, and a washing machine.