Your little one's first step in transitioning from bottle to cup. When baby’s ready, simply replace the vent and bottle nipple with the super soft sippy spout. The 100% silicone spout is easy to clean and is dishwasher safe (top rack only). Spout fits 5 oz/140 ml and 9 oz/270 ml Dr. Brown’s Options™ Wide-Neck bottles. BPA free.