Nûby has taken this one step further by adding the Nûby nipple with raised offset surfaces that assist in the eruption of teeth by gently massaging infant’s gums. The first and only Non-Drip nipple is uniquely designed to prevent drips and spills. With a pressure sensitive valve feature safely built right into the nipple, fluid only flows out of nipple with sucking actions of baby. This special valve closes when sucking action ceases, ensuring a leak-resistant bottle.