The new Options™ teats, have a scalloped base which allows air to vent through bottle when vent system is not used. The teats are made from high grade, super soft silicone.  

Keep in mind that the Bottle Nipple Chart serves as a general guideline for choosing a bottle nipple but is by no means an “end-all” solution. It is important to carefully watch the feeding habits of your little one. For instance, is your three-month-old not seeming to get enough from the bottle at feeding time? Moving her up from a Level One to a Level Two bottle nipple may be in order.