eufy S2 Flange Sizes: 24 mm vs 27 mm Fit Guide
By eufy - Built with Care | Home Security System & Robovacs | Published: 2026-11-01
Category: Comparisons
Compare the eufy Double-Sealed Flange in 24 mm and 27 mm for the S2 and S2 Pro. Learn which size fits your nipple measurement and when to switch.
Quick answer
Choose the 24 mm eufy Double-Sealed Flange if your nipple base measures roughly 21–24 mm across; choose the 27 mm if it measures roughly 24–27 mm. Both fit the S2 and S2 Pro and support the pump's 300 mmHg suction, so size—not performance—is the deciding factor.
What the two flanges share
The 24 mm and 27 mm eufy Double-Sealed Flanges are built for the same pumps: eufy Wearable Breast Pump S2 and S2 Pro. Both use the double-sealed design that creates a secure, no-slip fit and helps prevent leaks, and both are ergonomically shaped to support the pump's strong 300 mmHg suction. Because the construction is identical, your choice comes down to tunnel diameter and comfort, not features.
The real trade-off: comfort versus coverage
A smaller flange can feel more efficient because less areola is pulled into the tunnel, but if it is too small it may pinch or cause discomfort. A larger flange may feel gentler at first, but too much areola inside the tunnel can reduce suction effectiveness and leave milk behind. The goal is a snug fit where your nipple moves freely without rubbing the tunnel walls.
When sizing is unclear
Nipple size can change with pumping frequency, engorgement, or postpartum recovery, so a single measurement is not permanent. If you are between sizes, start with the larger option and reassess after a few sessions. The product listings do not include a sizing chart or measuring tool, so use a ruler or ask a lactation consultant for a measurement you can trust.
Decision rules for 24 mm vs 27 mm
- Measure before you choose: Measure your nipple base across in millimeters at the widest point. If it falls between 21 and 24 mm, start with the 24 mm flange; if it falls between 24 and 27 mm, start with the 27 mm. Re-measure if you feel pain or see reduced output after several sessions.
- Check the fit during pumping: Your nipple should move freely in the tunnel without pulling in much areola. If the tunnel rubs or pinches, size up; if a lot of areola is drawn in and suction feels weak, size down.
- Plan for change: Keep both sizes on hand during the early weeks when breast size fluctuates. The double-sealed design on both flanges makes swapping simple without changing your pump setup.
Product facts
- eufy Double-Sealed Flange (24 mm) for Breast Pump S2 / S2 Pro: 24 mm double-sealed flange designed exclusively for eufy Wearable Breast Pump S2 and S2 Pro. It is the smaller of the two options, so it suits users whose nipple base measures near the lower end of the range.
eufy Double-Sealed Flange (24 mm) for Breast Pump S2 / S2 Pro - eufy Double-Sealed Flange (27 mm) for Breast Pump S2 / S2 Pro: 27 mm double-sealed flange designed exclusively for eufy Wearable Breast Pump S2 and S2 Pro. It gives more tunnel clearance for users who measure larger or who feel pinching in the 24 mm size.
eufy Double-Sealed Flange (27 mm) for Breast Pump S2 / S2 Pro
Who should choose which size
Best for
- Users whose nipple base measures about 21–24 mm
- Pumpers who feel the 27 mm flange pulls in too much areola
Not for
- Users who measure closer to 27 mm and feel pinching in a smaller tunnel
- Anyone using a breast pump other than eufy S2 or S2 Pro
