The Dr. Brown's Baby Bottle Bundle includes 6 medium-fast flow Level 3 nipples for growing babies 6 months and up, along with a reusable bottle brush for easy cleaning. The Level 3 nipples feature an anti-colic internal vent system clinically proven to reduce colic, spit-up, burping and gas. The medium-fast flow rate provides a consistent vacuum-free feeding experience closest to breastfeeding, so baby can feed comfortably at their own pace. The breast-like nipple shape also encourages proper latching. Meanwhile, the bottle brush has a no-slip handle and suction cup for convenient storage, with durable BPA-free bristles and sponge to thoroughly clean both plastic and glass narrow and wide-neck bottles. The built-in ridge cleanly scrubs bottle nipples as well. Together, these components offer a complete solution for bottle-feeding older babies. The Level 3 nipples provide an easy transition from breast to bottle and back again, while the bottle brush keeps bottles hygienic for healthy feedings.