Premium Nurser Bottle Holders and Drop-Ins pre-formed liners in 4-oz for newborns and 8oz as baby grows. It also includes a breast milk storage kit to allow mom to pump, store and feed in the same liner – so, there is no need to transfer and potentially spill breast milk between bottles.2 4-oz. Premium Nurser Holders, 2 8-oz. Premium Nurser Holders, NaturaLatch slow flow silicone nipples, a set of breast milk storage components like 1 pump adapter ring, 1 liner ring, 2 nipple rings, 2 sealing disks, 30 Drop-Ins liners like 15 4-oz. and 15 8-oz. It reduces gas and colic and BPA Free.