Acts as a converter to help mums pump into wide neck bottles, such as made by Avent and Mamalok brands! All Unimom Breast Pumps are designed to be compatible with standard sized neck bottles, such as Unimom's own breastmilk storage bottles. However, some parents would rather use wide neck bottles from other brands. Simply screw this Unimom Wide Cap onto the shield of your Unimom Breast Pump and then connect to your wide neck bottle. Mums can now conveniently pump directly into any chosen bottle!