We are currently using formula.  I add water, add powder, and shake.  1 out of every four times I shake the bottle it leaks.  It has been so frustrating.

I called Avent and they told me that if I am using formula I need to stir the mixture.  The lady that provided instuctions was not friendly.  She also said if the bottle continues to leak you can purchase some extra piece? A gasket or something.  I am very unsatisfied with this product and I will not purchase it again, and I will not recommend it to a friend.

Anthony
Maple, NC