I bought these pumps because I had read such great reviews, but three times now the seal on this pump have become unsealed and as a result I have lost ALL of the milk that was pumped on the one side. The first time I assumed it was user error, the second time, I had bumped the seal (not hard but I thought “well apparently it was too hard for the pump”), but the third time ( just now -l was just sitting in the back seat of the car, we hit no bumps, I made definitely made sure that the seal was put on properly, and I started pumping.... 15 minutes into the pump, something felt off, and sure enough the entireContainer had leaked all over me. My shirt, sweatshirt, bra, and Pants are absolutely soaked. I'm devastated and now I need to figure out a new outfit where we are headed. The couple of times I have used it when the seal didn't come weundone that the pump did awesome. It has pretty good capacity for milk collection compared to other brands.