Wool covers made with Oeko Tex 100 certified Merino Wool. Each cover is one of a kind. Wool is highly absorbent. It will absorb up to 30% of its weight in moisture and is slow to feel damp, yet remains breathable, allowing maximum circulation around your baby's bum. It contains natural lanolin, which creates a waterproof barrier. Its elasticity means the cover fits well, yet moves with your baby. Wool is easy to care for. It doesn't need to be washed as often as other covers and it is naturally anti-bacterial.