I highly recommend these caps to anyone using the Standard Dr. Brown Baby Bottles. They stand up to steam sterilizing and dishwasher cycles. Caps are of good quality, and I find them to be a very good value! When the caps are used with the Dr. Brown Standard Baby Bottles, you are able to store breast milk, juice, milk, and water for future consumption. Packing baby bottles for travel, using the caps, assures no leaking of milk.