Wool Pillow. The wool pillow is truly adjustable – Inside the pillow you’ll find a filling of natural wool clusters, which we call ‘wool balls’. If you like a softer pillow – you can pull the clusters apart adding air and plumping up your pillow. If you like a flatter pillow – remove a suitable quantity of wool. If you like a deeper firmer pillow – we offer the option to purchase extra wool to stuff your pillow really full.