Willow Perfect Fit Bundle


When it comes to wearables, fit really matters — and fit starts with your flange. (It’s the cone-shaped funnel that seals over your nipple to transfer milk!)

Sometimes, fit can be tricky. The flange in your pump kit may not fit perfectly right out of the box, and your nipples will change in size over time. So our Perfect Fit Bundle makes it easy to take your measurements, experiment with inserts, and connect with a Sizing Specialist for personalized guidance.

What you’ll get:

  • A set of four inserts (sizes 13mm, 15mm, 17mm, and 19mm) that fit inside our 24mm flange to help create a more snug fit
  • Access to a 1:1 virtual session with a Willow Sizing Specialist

How it works:

  • Measure your nipples once your bundle arrives.
  • Add 0-2mm (if you’re pumping with Willow 3.0) or 1-3mm (if you’re pumping with Willow Go) to find your size. Our Digital Sizing Guide has step-by-step directions — and if you already have your pump, you can use the Nipple Sizing Tool that came in your kit.
  • If your flange still doesn’t feel comfortable, experiment with the other inserts. (Also, make sure you’re wearing a snug, stretchy pumping bra!)
  • Book a virtual session with a Sizing Specialist if you need additional support.

A few things to remember:

  • When pumping with Willow, a good flange fit is a snug flange fit. If you’ve pumped with a traditional pump (or another wearable), you could expect your Willow flange size to be different.
  • You should measure your nipples periodically — any time you feel discomfort or notice a change in your supply — and switch out your inserts as needed.
  • No matter what insert size you use, you’ll always place it into the 24mm flange that comes with your pump kit. Think of it as your “hub!”

Includes a Pump Kit + Sizing Inserts
Includes a Pump Kit + additional Flanges
Free shipping on all orders over $70

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