Willow Sizing Inserts
The Willow Sizing Inserts comes with 6 flange sizes, per Willow. Pack of two silicone sizing inserts for Willow flanges, offered in 13, 15, 17, 19, 21 and 27 mm.
- $19.99List price
How the Sizing Inserts stacks up
Against the 34 pump parts and flange inserts we track. The shaded band is where the middle half of them fall; the dot is this one.
Above the typical range for pump parts and flange inserts (3 to 5).
Within the typical range for pump parts and flange inserts ($10.99 to $52.49).
What sets the Sizing Inserts apart
Measured against the 34 pump parts and flange inserts we compare, from each maker's published specs.
- 3rd most flange sizesof the 17 pump parts and flange inserts with it published: 6
Next to its closest matches
- Willow Breast Pump Sizing KitNext to it, the Sizing Inserts is 1 more size; $5 less.
- Bodily Cushy Silicone Breast Pump FlangesNext to it, the Sizing Inserts is 2 fewer sizes; $7 less.
- Ameda Universal Soft Breast Pump Flange InsertsNext to it, the Sizing Inserts is $8 more.
Fit and use
As Willow lists it.
| Sizes | 13 mm, 15 mm, 17 mm, 19 mm, 21 mm, 27 mm |
|---|---|
| Material | silicone |
Fits these pumps
Willow says it fits: Willow 360, Willow Go, Willow Wave flanges (24 mm flange or 24 mm container insert).
Listed features
- Labeled HSA/FSA
Worth checking
- Fits only 24 mm flanges
- Two inserts per pack
Where to buy the Sizing Inserts
Prices and availability change. We may earn a commission from some links.
- Check for recalls: Search the agency's recall list with the model number and date code from the label: FDA recalls list.
- Breastfeeding and pumping: see the AAP's breastfeeding pages and the FDA's breast pump page. Check the label and the maker's instructions, and ask your pediatrician about your child.
Full specs
| Willow Sizing Inserts | |
|---|---|
| Type | Pump part or flange insert |
| List price | $19.99 |
| Fits | Willow 360, Willow Go, Willow Wave flanges (24 mm flange or 24 mm container insert) |
| Sizes | 13 mm, 15 mm, 17 mm, 19 mm, 21 mm, 27 mm |
| Material | silicone |
| BPA-free | Yes, per the maker |
| HSA/FSA | Eligible, per the maker or supplier |
More parts
- WillowBreast Pump Sizing Kit$245 flange sizes$24.99
- BodilyCushy Silicone Breast Pump Flanges$278 flange sizes$27
- AmedaUniversal Soft Breast Pump Flange Inserts$116 flange sizes$11.99
- AmedaCustomFit Breast Pump Flanges$105 flange sizes$10.99
- LansinohComfortFit Breast Pump Flange Inserts$93 flange sizes$9.99
- ZomeeUniversal Inserts$95 flange sizes$9.99
- Frida MomBreast Pump Flange Insert$73 flange sizes$7.99
- Pumpin' PalOptiFit Angled Flange Set$49$49.95
Where these specs come from
Last checked 2026-11-05. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.