LANACare's pure natural woolen diaper covers are of the finest quality. Made with felted wool, for maximal absorption. Natural lanolin content gives wool self-cleansing properties and removes urine odor. Medium (and Large) diaper covers have adjustable waist. Small opening in the outer seam of the woolen waistband allows you to access the inner elastic band, with button/buttonholes, to adjust for the perfect fit for your baby. Only soft wool touches your baby's sensitive skin.