Sleek, contoured designer bottle holds Drop Ins liners that collapse for an air free feed. This unique system has been clinically shown to help reduce gas, colic, and spitting up. And, a more comfortable baby means a happy baby and mom. The Playtex Drop Ins Premium Nurser Bottle features holders and pre sterilized, disposable liners that collapse to keep air out of the bottle and your babyand#8217;s system. After each feeding, the liner is discarded, so there is one less thing to clean. It reduces gas and colic and BPA Free.