I'm selling this because I didn't use it! It's new, unused, and unopened, but please refrain from purchasing if you are looking for a perfect product. This product contains 20 inner bags for baby bottles. This eliminates the need for sterilizing and washing baby bottles. Each bag is easy to take out, and it comes in a convenient zippered package for storage. Lightweight and compact, making it convenient for when you're on the go. For wide-mouth baby bottles, 240ml. The guide lines are suitable for preparing formula from 100-200ml.