For breast-feeding moms with the Medela Breast Milk Feeding and Storage Set, these replacement nipples are great to have on hand. Milk should drip out of a bottle -- not pour. If it comes out in a steady stream, it's time to replace the nipples! These wide base Medela nipples have a natural shape and anti-collapsible tip that helps your baby easily alternate between breast and bottle. Be prepared: You'll need extras eventually!