I think you mean BPA-free?
BPA is a form of plastic that leaks into the food/fluid at high temps after many uses of the plastic container, in this case bottles. So non-BPA-free bottles are usually changed after 3 mths of use.
You can go to the follow site for more info:
Philips - Bottles - Nipples - Storage - Out & About - Bottle feeding - Mother and child care
Click on "FAQs-some common questions about BPA and bottle feeding."