The new Dr Brown\'s Options+ range - the first convertible bottle that can be used with or without the green vent system. Dr Brown\'s bottles with the vent system have been clinically proven to help reduce wind related colic in babies which can cause pain and excess crying. Dr Brown\'s Options+ Anti-Colic Starter Kit has a unique internal green vent system that 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 Brown\'s for the relief of wind related colic. The breast-like teat shape is correctly contoured for a proper latch and a more natural bottle-feeding experience - perfect for switching from breast to bottle and back again. Each teat is specially engineered to offer the same consistent natural flow, so you and baby know what to expect in every feed. 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 Br Brown\'s scalloped designed teat allows air to vent through bottle when green vent system is not used for when baby\'s feeding it developed or parents just want the convenience of a teat vented bottle. The complete feeding system that grows with baby and helps alleviate the symptoms of windy colic. Help prevent colic with Dr Browns. The Dr Browns starter set contains the following2 x 5oz/150ml Bottles1 x 9oz/270ml Bottle, each bottle is supplied with a Level 1 Teat2 x Level 2 Teats 2 x Level 3 Teats