The Delta Baby Baby Sleep side positioner has been specially designed to keep babies comfortable and securely positioned on their side. Baby Sleep prevents babies from rolling over when asleep while allowing freedom of movement. The Baby Sleep can be used from birth onwards. In order to alternate the side on which the baby lies, the side positioner has to be turned around in such a way that the larger side is always at baby's back. At a certain stage of development (to be determined by the parents) the Delta Baby side positioner will no longer be needed and should be removed from the bed. The cover of the Baby Sleep is 100% cotton and can be removed and washed at 40 degrees.