Breast Pump Sizing Kit
$
24.99
FSA & HSA Eligible
1
In stock soon
Overview
Description
Find your perfect breast pump flange fit with a wide range of inserts designed for maximum pumping comfort and milk output.
The kit includes 13mm, 15mm, 17mm, 19mm, 21mm insert sets, a nipple sizing tool, pump sizing 101 guide and 1:1 virtual visit with a Willow Sizing Specialist.
Proper fit leads to comfort, and comfort leads to more milk output and fit starts with your flange.
What we about it
Helps you find the just-right breast pump flange fit.
Details
- Includes:
- 13mm, 15mm, 17mm, 19mm, 21mm insert sets
- Nipple Sizing Tool
- Pump Sizing 101 Guide
- 1:1 virtual visit with a Willow Sizing Specialist
- Connect with a Sizing Specialist for personalized guidance
- Use with any pump; they’re compatible with almost all 24mm flanges
- Fit most nipple sizes
Q&A
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Customer reviews
21 Ratings
1-10 of 21 Reviews
Convenient & easy to understand
This is a great kit with easy instructions on how to size yourself . I love the material of the flanges and how the kit comes with several sizes
Feb 26, 2026
Made sizing easy
This sailing kit came with all the bells and whistles compared to others! Not only did I get the traditional paper sizing cut out but also flanges to trial. The kit included a 1:1 consult with a specialist which I thought was amazing! I now have my correct flange sizes and am excited to pump with them 🙂
Feb 26, 2026
Great for moms motivated to pump as long as possible!
Throughout my 1yr+ pumping journey I changed insert sizes 3 times! I love that these are flush with the flange. Sometimes unexpectedly you need to change your size and this helps you determine a good fit by trying at least 2 or 3 sizes to get the best comfort and output! Will definitely ease the stress of waiting days for a new size to come in the mail; if you already have this at home in your pump toolkit!
Feb 25, 2026
Sizing kit is 10/10!!
There is nothing like Willow flanges. They fit perfectly in the Willow Go and corresponding pumps. They are the most comfortable I have ever tried. I never have an issue with pulling too hard or aggressively, the silicon is definitely the way to go with pumping. I love the diversity of sizing that comes with this pack, as my size changes during postpartum. When I had my first son I was originally a size 21, then went to 17 and back up to 19 to then pump for 15 months. I can’t wait to use this kit for my next pumping journey!!
Feb 25, 2026
Great product!
Easy to use & I’d even say informative/educational. Very step by step. Definitely purchase to find your right size.
Feb 25, 2026
Really nice, NECESSARY, little kit!
This flange sizing kit is really convenient. It’s honestly one of the best ideas ever. They’re very comfortable inserts in a range of sizes. I would definitely recommend to a new (or experienced!) mom!!
Feb 25, 2026
By far the best sizing kit on the market
I'm 7 months into pumping, and this sizing kit is easily the nicest one I've tried. The sizing tool and tips ended up with me getting a more accurate measurement and different flange insert size than when I had sized with a different kit, and my output has increased since switching to these! The flange inserts themselves feel so much higher quality and are much more comfortable- they don't feel pinchy at all. I would absolutely recommend this kit to anyone new or deep into their pumping journey!
Feb 24, 2026
Found this product to be
This review was collected as part of a promotion
Found this product to be very helpful and I was able to size myself correctly.
Feb 24, 2026
I love the comfort of
I love the comfort of these inserts. When starting your breastfeeding journey, it’s hard to know what your flange/insert size is and this allows you to find what you need without having to order multiple items at once. I was able to measure perfectly and find the inserts that suited me best.
Feb 23, 2026
10/10 recommend
Packaging was great and secured. The kit is amazing and has everything you need, from the measuring tool to different sizes of inserts. This is perfect especially for us moms who use different sizes. And not to mention when size changes during our breastfeeding journey. The inserts are longer than my current ones which is great (prevents the pinching I have with my current inserts) and are super soft. The perfect complement to the willow pumps.
Feb 22, 2026
