Take baby steps to sippy cups with Dr. Brown's 2-in-1 Transition Bottle Kit. Transition from bottle to cup one step at a time with this nipple-to-sippy conversion. Using the Dr. Brown's Narrow Neck Options bottle, just remove the vent and replace the bottle nipple with the super soft silicone sippy spout. , Includes a 250 ml Options bottle with level 3 nipple and a bottle sippy spout.