These are great for moms that make a lot of milk. Here’s a picture of a bag with 9oz in it - way more than the other brands will hold! The double zip top holds up. I don’t have a Lansinoh branded pump, but I still get these bags. I pump into bottles and bag them later anyway (pumping into bags with those adapter is not a closed system and I’m afraid germs may get in), so it doesn’t matter of my brand doesn’t match.