Works great! Fits perfect with my spectra pump! Haven’t actually used any breast milk in a bottle yet— my baby is only a week, but very easy and organized approach to pumping!!
Everything else sucks compared to these. I bought this for my sister and she loves it. The bags are lighter than having bottles attached to the pumps. The baby has such bad lgas when he doesn’t have the kiinde bags and has hiccups immediately. She didn’t have the attatchment for her manual pump while an hour away from home and the world was over for her and poor baby had hiccups immediate after eating. This system has been a life saver and has made the whole breatfeeding thing so much better!