MAM Ultivent Set of 2 Medium Flow Nipples - MAM Ultivent Bottle Nipples are made of ultra-soft silicone with silky-skin texture for easy transitioning between breastfeeding and bottle feeding.  Nipple is orthodontically shaped and non-collapsing while baby is drawing milk from the bottle.  Nipple size is embossed for easy differentiation between other nipples.  Available in 4 flow levels:  Slow flow, Medium flow, Fast flow, and Cross Cut.  Recommended for ages  Birth+.