No more boiling and scrubbing bottles. Playtex, the Disposable Premium Nurser is the only bottle system that uses a collapsible liner that you dispose of after each feeding. Not only do disposable liners save previous time, but they are the healthier choice because they use a pre-sterilized liner with every feeding. Drop-Ins pre-formed liners minimize air intake that can cause gas and other stomach discomforts. Easy-grip contoured nurser features a natural shape silicone nipple that allows baby to latch on easily and ease transition from breast to bottle. Both the leak-proof cap and retainer ring keep the nipple securely fastened on the nurser and prevent leaking.