Nipple Material Properties: PVC Free, Nitrosamine Free, Rubber Free, Phthalate Free, BPA Free Style: S small hole, M middle hole, L big hole, X does not suck, not shedding Size: S / M / L / X Flow Velocity: S, M, L flow, can flow naturally, the larger the hole, the more flow, X does not suck, does not flow Mouth size: wide neck teat Material: Silica gel Packaging: in bag Baby nipple feeder: baby feeding Baby Safety: Baby Care Baby products: Baby feeding bottle accessories Type: Cork Tips: X does not suck, does not flow ; S, M, L will flow naturally, please choose according to the age of the baby Sterilized with hot water before use. The nipple should be changed every 20 days to 30 days