Brand-name flanges cost about $15 each and you're going to need more than one size. You just won't know which size until you're actually using the pump, which is a fun surprise nobody prepares you for.
Maymom flanges work just as well, fit both the Spectra and the Pumpables, and come in multi-size kits for less than one Spectra flange costs. Order a kit before the baby arrives, try a couple sizes once things are happening, and stop overthinking it.
The guides all say to measure ahead of time. The guides are optimistic. Almost everyone I know ended up adjusting anyway.
We went deeper on breast pumps here.
This post contains affiliate links. If you buy something through one of our links, we may earn a small commission — at no extra cost to you. We only link to things we've actually used and would tell a friend about.
Part of our All Things Breastfeeding & Pumping guide.