I bought this to use with my Avent bottles (which by the way LEAK) and I was very disappointed. My doctor told me to pump to stimulate my milk production which was coming in slowly. I could not get very much with this and needless to say it was not helping. Once I started using a Medela Electric pump, I got tons of milk! I was skeptical about the price, but it's totally worth it if you want to be able to use a pump on a regular basis.