Features One, two or three holes as well as a Y-cut version instead of varying the size of the suction hole Four flow rates — slow (0M+), medium (3M+), fast (6M+), and Y-cut (6M+) Elongated vent helps reduce spit-ups and colic 100% plastic free infant nipple crafted from medical grade silicone Each pack contains two Natural Vent Nipples of the same flow rate Meets all FDA, CPSC, EN14350, European Commission 10/2011, German LFGB regulations and/or guidelines Patent pending design