Any gauge of flat bed knitting machine may be used. Each uses worsted weight yarn but on smaller gauge machines, every other and every third needle are used. Bulkies use every needle. Knitting is made very loosely, then felted. Gauge after felting is about 4 stitches/6.7 rows per inch. Yarn must be 100% untreated wool. Exact size will vary with yarn choice and degree of felting.