"I love that the tunnel is clear, this really helps with placement, in turn helping with comfort. I also like that the clear part provides enough grip to keep my nipple in place which prevents the leakage issue I was having with the 2nd gen ones.I am almost 7 months postpartum and I have been pumping since my daughter was 4 months old. I use a Spectra S1 with my Lansinoh pump part, and XS pumpin pals. I usually get around 44 to 48 oz per day, pumping about 4 to 5 times a day, I am regulated. I tried out the flange on my left breast which at this time of day gives me just a little bit less than my right. It had been 3 hours since my last pump, so I expected about 3 oz from each, usually the left gives 2.75 and the right gives 3.25. After 20 mins my left, with the lacTeck gave just a little under 3 and my right gave me right at 3. The lacTeck was more comfortable to use, the XS pumpin pals have been making me a little tender lately. The 21mm is still just ever a little big for me, I really wish they did come in a 18mm, but I understand 21 and 24 would the most popular sizes to manufacture. I am definitely impressed with the increased comfort. I'm looking forward to seeing how they go in the morning. I noticed that the diaphragm was expanding more on the side I used the lacTeck, which meant that there was more suction/stimulation." - Jamie