Hi folks -- just thought I'd let you know that if you're using the AVent ISIS manual pump and you wear through the 3 little white valves that they include in the box (as I did), I've found out how to get more. Just call the Avent customer service line, explain your problem and they will send you 3 more valves for free. They can't be purchased anywhere -- seems like Avent just decided to mail them to anyone who complains. I actually bought a second pump the first time my valves wore out because it was an emergency and I need to pump urgently the next day and I couldn't find valves to buy. Then I wore through the valves on my second pump and decided to call Avent. They weren't at all surprised, it seemed kind of routine. Just thought I'd let you know in case you're in a similar situation.