Dr. Brown's Options Glass Wide-Neck Bottle is the market's first convertible bottle that can be used with or without the vent system. It is now available in a glass version that some parents prefer. This bottle features an ergonomic wide-neck design that is easy to fill and hold. The silicone nipple also has a broader base, which some breastfeeding moms prefer. The new vent system is designed to grow with baby, and we rmend using this system to experience all the health benefits of our bottle. Gender: unisex.