An excellent kit for complimentary feeding or to try dr browns bottles. The enhanced design of the Dr browns options+ anti-colic bottle is clinically proven to reduce windy colic due to dr browns unique 100% vacuum-free vent system. Dr browns options+ bottles offer an easy and comfortable way to feed your little-one, adapting to their needs as they grow. With the unique design, this bottle can be used with or without the removable internal vent system, transforming it into a teat-vented bottle for more convenience. Use dr browns options + bottles from birth dont wait until your baby develops colic! The unique internal green vent system continues to create 100% vacuum free feeding, which is clinically proven to help reduce wind related colic.