Use Playtex Drop-Ins Pre-Formed Soft Bottle Liners with Playtex Nursers. Pre-sterilized and disposable for a fresh, clean liner for every feeding. Soft bottle liners collapse as baby feeds, for less air, which means less gas, spitting up and colic discomfort. Pre-formed - so convenient and easy to use, you can even assemble with one hand! Pre-calibrated ounce markings for easy measuring. 100% leak-free - guaranteed.    Box of 50 liners.