I have chosen not to enter into the discussion of S vs L but feel the time is right to do so now. The first item on the market does work by vacuum. One problem I observed with it was that once the flow was activated, it did not always stop flowing! This meant it had some of the same drawbacks as a bottle with large teat hole. Other problems I observed was bag breakage (what a mess!) and difficulty getting replacement parts, etc. Also cost put off a lot of people. The other device is not cheap, a continuing problem, particularly when I see couples who really need the full-size rather than the hospital-size/"disposable"/single-use version. However, the S, which cam eon the market later, can be adjusted as to flow, both rapidity and amount, quite easily. I have not had dififuclites with baby being "addicted" to it. I have had mothers "addicted"/dependent on both devices. That makes for an interesting consult discussion, let me tell you! %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% "We are all faced with a series of great %% %% opportunities brilliantly disguised as %% %% impossible situations" - definition of a %% %% lactation consulting service. %% %% Kathleen G. Auerbach, PhD, IBCLC %% %% [log in to unmask] Homewood, Illinois USA %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%