Dr. Brown's Options 2-Pack 5 oz. Wide-Neck Glass Bottles Dr. Brown's bottles are an excellent choice for your baby. Proven to help maintain vitamins A, C, and E during bottle feeding, these bottles have positive pressure with no vacuum feeding and help reduce colic, spit-up and gas. Dr. Brown's Options Wide-Neck Glass Bottles offer a wonderful feeding experience for your little one using innovative vent technology similar to breastfeeding Designed to fit most breast pumps Set includes: 2 wide neck glass bottles 2 nipples 2 sealing caps Glass Dishwasher safe Made in USA Dr. Brown’s Options Bottle Two Vent Options. One Proven Bottle. Dr. Brown's Options Glass Wide-Neck Bottle grows with the needs of your baby and offers healthy benefits whether your little one is experiencing feeding challenges or not. Options give you the power of choice. Internal Vent System Our Dr. Brown's bottle features a two-piece internal vent system that works unlike any other bottle design. Dr. Brown's fully-vented design is closest to breastfeeding. The internal vent system and silicone nipple work together to provide a controlled flow so babies feed at their own pace. Air enters the bottle collar and routes directly through the internal vent system. The air channels through the vent tube, bypassing the breastmilk or formula, settling to the back of the bottle. The vent prevents vacuum pressure, aeration of the breastmilk or formula, and nipple collapse. Baby feeds comfortably while milk flows freely, similar to a breastfeeding experience. Health Benefits The Dr. Brown's vent system reduces air bubble oxidation to help preserve bottle milk nutrients. Dr. Brown’s fully-vented bottles help preserve levels of three important nutrients for infants, vitamins C, A, and E. The vent system reduces air bubble oxidation of the milk, which is fragile and susceptible to nutrient loss.