Most pumps ship with 24mm flanges. Most moms need between 15 and 19mm. That gap is almost always the reason pumping feels harder than it should.

This free 8-page guide walks you through:

• Why size matters. Wrong size means pain, poor output, and the feeling your body isn't cooperating. Usually it isn't. It's the fit.
• What correct fit looks like. Too large, too small, wrong shape, elastic nipples — illustrated clearly.
• How to measure at home. Includes a printable nipple ruler.
• Hard plastic vs silicone. What the difference is and who silicone works best for.