# Replacement parts for Willow breast pumps Which replacement parts fit a Willow breast pump? Willow Pump Willow Sync Flange Set 24mm \(2\-pack\): Designed for Willow Sync pumps\. Willow Pump Willow 360® Milk Container Insert Replacement Set \(2\-pack\): The inserts snap right into Willow Milk Containers\. Willow Pump Willow Sizing Insert Set: They are designed for the perfect fit and performance with Willow and make pumping more comfortable for mamas with smaller flange sizes\. Willow Pump Willow 360® Container Set \(2\-pack\): The containers are reusable and are an alternative to pumping directly into storage bags with the Willow pump\. Willow Pump Willow Go® Pump Diaphragm Set \(2\-pack\): For use only with the Willow Go pump\. Willow Pump Willow Go® Container Duckbill Valve Set \(2\-pack\): For use only with the Willow Go pump\. ### 1. [Willow Pump Willow Sync Flange Set 24mm \(2\-pack\)](/products/ucp/onewillow-com/7967832408157) (sold by onewillow\.com) Designed for Willow Sync pumps\. - Pump compatibility: Designed for Willow Sync pumps\. (listing) - Pack size: Sold as a 2\-pack\. (listing) - Size: The flanges are 24mm\. (listing) ### 2. [Willow Pump Willow 360® Milk Container Insert Replacement Set \(2\-pack\)](/products/ucp/onewillow-com/3792177889373) (sold by onewillow\.com) The inserts snap right into Willow Milk Containers\. - Pump compatibility: The inserts snap right into Willow Milk Containers\. (listing) - Pack size: The set is a 2\-pack of inserts\. (listing) - Size: It is offered in 21mm, 24mm and 27mm\. (listing) ### 3. [Willow Pump Willow Sizing Insert Set](/products/ucp/onewillow-com/6552686755933) (sold by onewillow\.com) They are designed for the perfect fit and performance with Willow and make pumping more comfortable for mamas with smaller flange sizes\. - Pump compatibility: They are designed for the perfect fit and performance with Willow and make pumping more comfortable for mamas with smaller flange sizes\. (listing) - Pack size: The sizing inserts come as a 2\-pack\. (listing) - Size: Sizes offered are 13mm, 15mm, 17mm, 19mm, 21mm and 27mm\. (listing) ### 4. [Willow Pump Willow 360® Container Set \(2\-pack\)](/products/ucp/onewillow-com/3792104390749) (sold by onewillow\.com) The containers are reusable and are an alternative to pumping directly into storage bags with the Willow pump\. - Pump compatibility: The containers are reusable and are an alternative to pumping directly into storage bags with the Willow pump\. (listing) - Pack size: The set is a 2\-pack of containers\. (listing) - Size: It is offered in a 24mm size\. (listing) ### 5. [Willow Pump Willow Go® Pump Diaphragm Set \(2\-pack\)](/products/ucp/onewillow-com/6705010212957) (sold by onewillow\.com) For use only with the Willow Go pump - Pump compatibility: For use only with the Willow Go pump (listing) - Pack size: Sold as a 2\-pack (listing) - Size: - ### 6. [Willow Pump Willow Go® Container Duckbill Valve Set \(2\-pack\)](/products/ucp/onewillow-com/6705010245725) (sold by onewillow\.com) For use only with the Willow Go pump - Pump compatibility: For use only with the Willow Go pump (listing) - Pack size: Sold as a 2\-pack (listing) - Size: - Every value in the table is a fact RoboTrunk checked, linked to the page it came from\. A dash means no checked fact fills that cell\. Prices and stock change, so this page prints neither: each product name links to its RoboTrunk page, which shows them live\. Written 2026-10-24T23:11:04.979Z. This page is published by RoboTrunk, a store built for shopping agents. The store named on this page sells the product and ships it. RoboTrunk is not the seller and never holds the money. Buying works in one path. RoboTrunk's tools prepare a checkout at that store, then hand back a short-lived link. The person approves the total; once RoboTrunk has checked the store's total against it, the person is given the checkout link to tap in their own browser, or, if the person prefers and gives permission, their agent may open the link and finish there, and payment always happens on the store's own checkout page. RoboTrunk never takes the payment or sees a card. Where the rest of this site is: - /agent/story.md is what RoboTrunk is and how it works, in full. - /agent/tools.json is every tool, its arguments and its answers. - /agent/merchants is every store you can buy from through RoboTrunk. - /products/ucp is every store's indexed products. - /products/search is one search across every store, in plain words. - [What RoboTrunk is](/agent/story.md) - [Every tool, in your browser through WebMCP](/agent) - [The tools and how to call them](/agent/tools.json) - [The stores you can buy from](/agent/merchants) - [Every store's products](/products/ucp) - [Search every store at once](/products/search)