Developed with Pediatric Feeding Specialists, the Evenflo Feeding Balance + Wide Neck Nipple is designed to support healthy bottle feeding without interfering with your breastfeeding journey. The unique, naturally-sloped nipple promotes a healthy wide latch for your baby by providing a proper resting place for their lips, helping to decrease mouth fatigue. The effective 1-piece integrated vent helps prevent colic, gas, and fussiness with no extra parts to clean or lose. The slower flow rate helps prevent chugging, allowing for a calm, gulp-free feeding at baby's pace. This combo pack includes one Balance + Wide Medium Flow Nipple (3-7 months) and one Balance + Wide Fast Flow Nipple (8+ months), so you can find the best flow for your baby. Indicators that it may be time to move to the next flow nipple include, but are not limited to: your baby collapses the nipple during a feeding, starts fussing with the bottle, unlatches and re-latches throughout the feed, acts agitated, bites or tugs on the nipple, and/or sucks several times before swallowing. The Balance + Wide Neck Nipple is compatible with the Balance + Wide Neck Bottle. Evenflo Feeding nipples are 100% free of BPA, polycarbonates, PVC and phthalates, and are also made of FDA-approved food grade material.