Willow Sizing Insert Set (2-pack)
Find your flange fit. Pump with confidence.
When it comes to wearables, sizing is different — you'll need a fit that's more snug. Most moms find that adding 1-3mm to their nipple size (or 0-2mm if you're pumping with Willow 360) results in optimal output and comfort.
Still need your nipple measurements? Try our sizing guide
|
Measured Nipple Size |
Willow Recommended Size Flange / Insert |
| 9-11mm | 13mm insert in 24mm flange |
| 12-13mm | 15mm insert in 24mm flange |
| 14-15mm | 17mm insert in 24mm flange |
| 16-17mm | 19mm insert in 24mm flange |
| 18-20mm | 21mm flange |
| 21-23mm | 24mm flange |
| 24-26mm | 27mm flange |
Sizing inserts can only be used with a 24mm flange or 24mm container insert.
Questions? Our experts can help.
1-888-WILLOW-3
How To Find Your Nipple Size
Step 1: Get a measuring tape
Measure the diameter of your nipple at its base while erect to determine its size accurately.
Step 2: consider sizing up
Most moms find that adding 1-3mm to their nipple size results in optimal output and comfort.
Step 3: take a look at our chart
Match your measurements to our sizing chart to find your recommended size flange / insert.
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Frequently Asked Questions
- Vanessa F.Verified BuyerRated 5 out of 5 stars4 days agoHelped increase my output
At first wasn’t sure if it was the pump after using the insert my output changed immensely. Use the sizing kit and sometimes I alternate between 2 diff sizes of inserts depending on how full I am 🙂
- Diana J.Verified BuyerRated 5 out of 5 stars6 days agoPerfect Fit
The Willow sizing inserts are great. The fit is snug and comfortable.
- Amanda W.Verified BuyerRated 1 out of 5 stars1 week agoHurts
I’ve tried two inserts and the pump hurts.
WPWillow Pump5 days agoHi, Amanda! Thank you for taking the time to share your review of our Sizing Inserts!
Sizing always matters! Pumping should not be painful & when we are tense, nervous or in pain, the volume we pump can be reduced. We have learned with time, that Moms have more comfort and success by measuring and reducing the flange size to fit their individual anatomy. Flange sizing inserts help us achieve that ideal fit for you, which can make all the difference in your overall experience with your Willow pump. So, getting comfortable (in the correct sizing) leads to a great pumping session and better overall experience. For Willow 360™, we recommend using your exact sizing to match the measurement of each side. For Willow Go®, we recommend adding 1-3mm to your measurement for an ideal starting point.
If you would like further sizing assistance, please feel free to check out our Mom Coach services here: https://help.onewillow.com/s/sizing, we'd love to help! - Michelle S.Verified BuyerRated 5 out of 5 stars1 week agoComfort for small sizes
These provide more comfort while pumping and have a small size that works for me. (Also fit in spectra)
- Kelli M.Verified BuyerRated 5 out of 5 stars1 week agoIncrease output
Fit great and so comfy! So important to have the right size flange
