I have a client who has twins (I previously posted about these babies; they had lots of bottles, but were easily transitioned to breast once strong enough.) One baby has colostomy bag and has just left for the East Coast to undergo surgery for bowel blockage. Mother was sold a PNS by someone at the hospt. where she delivered. I personally do not sell the PNS, preferring in a clinical practice to only deal in clinical grade pumps. It was presented to her as a clinical grade pump. She had (as you may recall) very sore nipples as a result of nipple candida. This was successfully treated, however nipples remained very, very sore. I checked positioning and did not observe nipple distortion, nor detect any odd oral anatomy or function which would suggest sucking issues. Besides, due to the soreness, mother was only putting babies to breast once or twice a day. She was pumping like crazy with her PNS. She called in despair, wanting to keep at least the ill twin on human milk through his surgery. I had already suggested lubricating pump flange. I had her come in and pumped her on both the classic and the lactina. Niether hurt. I sent her home with a lactina because it is lighter weight and she can travel with it. She worked with it for a week before leaving for NY and her nipples were vastly improved. I think that the diaphragm release is slower than the piston release, sustaining the negative pressure for slightly longer. Some women (working moms) have told me they like the sensation of slightly stronger suction. It may be inappropriate for women who have had nipple problems. Barbara