Variable flow rate controlled by feeder and baby: You and baby are in control of the flow of milk, leading to a more natural feeding experience;Sensitive to baby's feeding efforts: This innovative design rewards the weakest suck;One-way valve: Prevents flooding so baby is never overwhelmed with too much milk;Sterile packaging: Baby and breastmilk are safe with sterile packaging. Made without BPA: All parts that come into contact with breastmilk are not made with BPA;Version with 80 mL container includes Mini SpecialNeeds teat: Smaller teat for smaller or premature babies