The noogleberry system has 2 domes that go over the breasts with two tube coming off of the domes. The tubes are converted into 1 tube by a tee piece. This tube is attached to the pump. It is a manual pump, so you pump yourself. You pump to suck the air out of the domes, this makes your breasts swell in the domes. The noogleberry increases circulation in the breasts as well as producing tension-induced tissue growth. I'm a 32AA, although 32A also fits me, and I got the mediums as Lucy suggested. If you're still unsure, you can email Lucy and ask her what size domes would be best for you. I've been noogling for only 1 week, and I already love it. Good luck!