Compatible with the haakaa and Mason Baby Bottles and tranforms it into a sippy cup. The kit includes 4 sippy spout nipples. Bottle not included. Easy transition since baby is already familiar with the bottle. Soft spout for easy transition. The nipples are made from food-grade silicone. Does not contain any BPA, Phthalates, PVC, Latex or Lead. Gentle on the gums. Variable Flow. Line cut. Easy to clean. No extra parts to wash. Compatible with the haakaa and Mason Baby Bottles and converts them into a Sippy Cup! It will make the transition easy since your baby is already familiar with the bottle. Our silicone spouts are soft and gentle on your baby's gums.