The Medela Spare Teats for Haberman Feeder is the ideal feeder accessory for your infant. This teat features a valve slit, which allows proper flow of milk. It has a three line marking in the teat, which indicates three levels of streams for regularized flow of milk. Product Features: Has a valve slit which allows the regulation of the flow Three lines on the side of the teat indicate three different streams: short line for minimum flow, average flow line medium and long line for maximum flow One-way valve prevents the intake of air from the child and allows him to swallow slowly Made of silicone material Should be replaced regularly, as shown in the instructions for use