Replacing Your Parts
Frequently Asked Questions
Our bestselling pump, ranked #1 in comfort for more milk output. App-controlled, hospital-grade suction, SplashGuard™ containers. Kit comes with 21 and 24mm flanges.
Willow 3.0 is now 360. 100% leak-proof, hospital-grade, app-controlled, and supported by 360 Care. Comes with 21mm inserts & 24mm flanges.
The first-ever 2-in-1 double manual pump with an ergonomic handle that also connects to your traditional pump for a hands-free experience—no charging required. Includes 24mm flange made of soft silicone for a smooth fit and optimal milk flow.
Meet the Breast Milk Cooler that cools faster and stays colder for up to 24 hours vs. leading milk coolers.* Plus, with new sizes, colors, and two ways to cool, this patent-pending Cooler safely and stylishly lets moms store milk wherever the day takes them.
*Compared to leading milk coolers in Eurofins 2026 controlled, third-party testing
Protect your pump on-the-go with our sleek, sturdy, and easy-to-clean carrying case.
The all-in-one cleaning kit for pump parts, bottles, and more. Just add your favorite soap!
Made with plant-based ingredients to remove breast milk residue from your Willow pumps and parts.
Everything you need to prioritize breast care and comfort, catch every drop of hard-earned breast milk, and feed with more confidence. Plus, every purchase includes access to a virtual appointment with an International Board Certified Lactation Consultant (IBCLC), as well as a free digital feeding course.
Soothe sore breasts and help promote output with temperature-changing gel packs that turn blue at room temperature, white when hot, and purple when cold.
Find your perfect breast pump flange fit with a wide range of inserts designed for maximum pumping comfort and milk output.
Our reusable containers (available in 5 oz and 7 oz) now feature a silicone Splashguard to give you more peace of mind (and less mess) when pumping.
Meet the Breast Milk Cooler that cools faster and stays colder for up to 24 hours vs. leading milk coolers.* Plus, with new sizes, colors, and two ways to cool, this patent-pending Cooler safely and stylishly lets moms store milk wherever the day takes them.
*Compared to leading milk coolers in Eurofins 2026 controlled, third-party testing
Put your breast milk organization on autopilot. Featuring our premium Breast Milk Storage bags with SmartStash capability–a unique scannable code that lets you auto-input and track bags in your digital stash–and Flatteners to evenly organize and freeze your physical stash, this combo does the mental math for pumping moms.
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

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.
2 Willow 360 Milk Containers
You can shop all Willow 360 accessories here.
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For optimal output, replace every 90 days (or when you notice discomfort or signs of wear).
Yes, you can. Simply pay for your breast pump and accessories using your FSA/HSA debit card at checkout, or pay with another credit card and submit your receipt to your plan administrator for reimbursement.
The right size is key for maximizing comfort and output. Willow offers flanges and containers in size 21mm, 24mm, and 27mm. If you measure smaller than 21mm, we offer Sizing Inserts in sizes 15mm, 17mm, 19mm that snap into our 24mm Flanges and Containers. We strongly recommend measuring yourself to determine your Willow size as it might be different from other pumps you’ve used. Unsure of your size? Visit our sizing guide or check out our exhaustive guide on how to measure your flange size which includes pro tips from Willow’s lactation consultants.
After every use, you can wash by hand or pop the parts in the dishwasher, top rack only.
It’s important to wash breast pumping parts after every session to avoid the growth of bacteria. We also suggest you do not store your Container in the fridge or the freezer. This can lead to decreased performance for the Container.
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