Dr Brown's Options 270ml/9oz bottle comes with a level 1 teat & vent cleaning brush. The same trusted bottle, with added benefits The new Dr BrownÕs Optionsª - the first convertible bottle that can be used with or without the green vent system. The unique internal green vent system continues to create 100% vacuum free feeding, which is clinically proven to help reduce wind related colic. This is what makes 9 out of 10 Healthcare Professionals recommend Dr BrownÕs for the relief of wind related colic. As baby becomes more developed the bottle can be used without the green vent system to work more like a conventional, teat-vented bottle. The new Dr BrownÕs scalloped designed teat allows air to vent through bottle when green vent system is not used for when babyÕs feeding it developed or parents just want the convenience of a teat vented bottle.