Options Narrow 2oz Bottle 2-pack include 2 preemie nipples. Options narrow bottles can be used with or without the vent system to cover all parents' needs. The vent system is designed to grow with baby, and we recommend using this system to experience all the health benefits of our bottle. It helps reduce feeding problems, helps digestion and helps preserve vitamins. Preemie nipples included for a slow flow. BPA-, PVC and phthalate-free. Suitable for newborns and older.