---
title: "spectra replacement pump parts 21mm — Niche Verdict: Skip it (35/100) | Amazon United States - Flapen"
canonical_url: "https://flapen.com/amazon/research/us/baby-products/spectra-replacement-pump-parts-21mm"
last_updated: "2026-07-13T23:11:16.422Z"
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  description: "brand-locked demand (top 5 brands take 100% of clicks) — spectra replacement pump parts 21mm doesn't clear our bar today."
  "og:description": "brand-locked demand (top 5 brands take 100% of clicks) — spectra replacement pump parts 21mm doesn't clear our bar today."
  "og:title": "spectra replacement pump parts 21mm — Niche Verdict: Skip it (35/100) | Amazon United States - Flapen"
---

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# **spectra replacement pump parts 21mm**

**Skip it**

Brand-locked demand (top 5 brands take 100% of clicks) — this niche doesn't clear our bar today.

Market size 11Growth 21Conversion 96Competition 13Returns 25Price range 95Avg price 95Brand share 0Review moat 44Quality gap 42

**Conversion**

**Incredible****13.2%**

search→purchase rate — share of searches ending in a sale

**Avg price**

**Incredible****$23.78**

avg listing price — sweet spot $15–$100

**Price range**

**Incredible****$16.74–$34.93**

cheapest to priciest tracked listing — scored on the share inside $15–$100

**Review moat**

**Okay****2,075.44**

avg incumbent reviews — the moat a new listing must climb

**Quality gap**

**Okay****4.5★**

avg incumbent rating — lower means beatable quality

**Returns**

**Bad****6.0%**

return rate — above 6% kills the launch gate

**Growth**

**Bad****-8.9%**

90-day search growth — must beat 0% to launch

**Competition**

**Bad****84%**

top-5 click share — a locked-up shelf

**Market size**

**Bad****$42K**

$42K/yr · 14K searches

**Brand share**

**Bad****100%**

top-5 brand share — brand-locked demand

## **Competition**

The top 5 products capture 84% of clicks — a locked-up shelf that new listings rarely crack.

**Brands**

**5 **▼falling

**Sellers**

**8**

**Top-5 brand share**

**100%**

**Open market**

**0%**

- Maymom51% - afontoto23% - Momstouch19% - MilkFlow4% - Hranio4% - Open — no brand owns it (0%)

## **Product shelf**

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

0%10%$4K20%$8K30%$13K40%$17K101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 9 tracked products in this niche — three views at once, no toggling.

### **Top sellers**

by 90-day click share

[1![Maymom Pump Parts Compatible with Spectra S2 S1 Replacement Kit for Spectra Pump Parts 21mm Flange Duckbill Valve Tube Bottle Backflow Protector Not Original S2 Accessories](https://m.media-amazon.com/images/I/41OQAxFsWEL.jpg)**Maymom Pump Parts Compatible with Spectra S2 S1 Replacement Kit for Spectra Pump Parts 21mm Flange Duckbill Valve Tube Bottle Backflow Protector Not Original S2 Accessories**Maymom**$32.51**4.6★9,124 rev](https://www.amazon.com/dp/B07LBPPGD7) [2![Momstouch 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Breastpump Replacement to Spectra Pump Parts Not Original Replace Accessories.](https://m.media-amazon.com/images/I/41pnMCF1tnL.jpg)**Momstouch 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Breastpump Replacement to Spectra Pump Parts Not Original Replace Accessories.**Momstouch**$16.74**4.3★592 rev](https://www.amazon.com/dp/B0CKQK8GWG) [3![Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories](https://m.media-amazon.com/images/I/41ExBGY+MmL.jpg)**Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories**afontoto**$20.08**4.4★611 rev](https://www.amazon.com/dp/B0DNQ49L24) [4![Maymom 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Replacment Pump Parts Not Original Spectra Flange Duckbill Valve](https://m.media-amazon.com/images/I/41-UdS8uYwL.jpg)**Maymom 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Replacment Pump Parts Not Original Spectra Flange Duckbill Valve**Maymom**$18.80**4.6★6,022 rev](https://www.amazon.com/dp/B0863NBHRX) [5![21mm Flange Maymom Pump Parts Compatible with Spectra S2 S1 9 Plus Breastpump Not Original Spectra S2 S1 Replacement Pump Parts Accessories Small Flange](https://m.media-amazon.com/images/I/41+LaSjm1QL.jpg)**21mm Flange Maymom Pump Parts Compatible with Spectra S2 S1 9 Plus Breastpump Not Original Spectra S2 S1 Replacement Pump Parts Accessories Small Flange**Maymom**$30.41**4.6★1,226 rev](https://www.amazon.com/dp/B07X8FDMMV)

**~~View all top sellers →~~**

### **Newest**

by launch date

[![Breast Pump Accessories Compatible with Spectra S1 S2 S9 Plus Replacement Pump Parts 2 Sets with 21mm Flanges Spectra 10oz Bottles Duckbill Valves Tubing Backflow Protectors Not Original](https://m.media-amazon.com/images/I/41O0z0LzUBL.jpg)**Breast Pump Accessories Compatible with Spectra S1 S2 S9 Plus Replacement Pump Parts 2 Sets with 21mm Flanges Spectra 10oz Bottles Duckbill Valves Tubing Backflow Protectors Not Original**afontoto**$20.47**72 rev8mo ago](https://www.amazon.com/dp/B0FY62CVSJ) [![Pump Replacement Parts Compatible with Spectra S1/S2/9 Plus Not Original Accessories Full Set Include 21mm Flanges Valves Tubings and BottlesBackflow Protectors and Duckbills](https://m.media-amazon.com/images/I/51BQGg2wvPL.jpg)**Pump Replacement Parts Compatible with Spectra S1/S2/9 Plus Not Original Accessories Full Set Include 21mm Flanges Valves Tubings and BottlesBackflow Protectors and Duckbills**MilkFlow**$21.01**378 rev1y ago](https://www.amazon.com/dp/B0FCSS727W) [![Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories](https://m.media-amazon.com/images/I/41ExBGY+MmL.jpg)**Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories**afontoto**$20.08**611 rev1y ago](https://www.amazon.com/dp/B0DNQ49L24) [![Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories](https://m.media-amazon.com/images/I/41XV4NS5k9L.jpg)**Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories**afontoto**$34.93**611 rev1y ago](https://www.amazon.com/dp/B0DNQ4BXPN) [![Hranio Breast Pump Parts Compatible with Spectra Replacement Pump Parts 21mm Flange Spectra Pump Parts S1 S2 Replacements Full Set 2 Set (Full SET-21MM)](https://m.media-amazon.com/images/I/41LKFUpxtgL.jpg)**Hranio Breast Pump Parts Compatible with Spectra Replacement Pump Parts 21mm Flange Spectra Pump Parts S1 S2 Replacements Full Set 2 Set (Full SET-21MM)**Hranio**$19.05**43 rev2y ago](https://www.amazon.com/dp/B0D7VDDZB8)

**~~View all new products →~~**

### **Trending**

90-day click momentum

[![Breast Pump Accessories Compatible with Spectra S1 S2 S9 Plus Replacement Pump Parts 2 Sets with 21mm Flanges Spectra 10oz Bottles Duckbill Valves Tubing Backflow Protectors Not Original](https://m.media-amazon.com/images/I/41O0z0LzUBL.jpg)**Breast Pump Accessories Compatible with Spectra S1 S2 S9 Plus Replacement Pump Parts 2 Sets with 21mm Flanges Spectra 10oz Bottles Duckbill Valves Tubing Backflow Protectors Not Original**afontoto**$20.47**4.6★**▲ 297%**](https://www.amazon.com/dp/B0FY62CVSJ) [![Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories](https://m.media-amazon.com/images/I/41XV4NS5k9L.jpg)**Pump Parts Compatible with Spectra S1/S2/9Plus/SG Breastpump Full Set Replacement Parts for Spectra Include 21mm Flange Duckbill Valve Backflow Protector Tube Bottle Not Original S1/S2 Accessories**afontoto**$34.93**4.4★**▲ 24%**](https://www.amazon.com/dp/B0DNQ4BXPN) [![Hranio Breast Pump Parts Compatible with Spectra Replacement Pump Parts 21mm Flange Spectra Pump Parts S1 S2 Replacements Full Set 2 Set (Full SET-21MM)](https://m.media-amazon.com/images/I/41LKFUpxtgL.jpg)**Hranio Breast Pump Parts Compatible with Spectra Replacement Pump Parts 21mm Flange Spectra Pump Parts S1 S2 Replacements Full Set 2 Set (Full SET-21MM)**Hranio**$19.05**4.6★**▲ 14%**](https://www.amazon.com/dp/B0D7VDDZB8) [![21mm Flange Maymom Pump Parts Compatible with Spectra S2 S1 9 Plus Breastpump Not Original Spectra S2 S1 Replacement Pump Parts Accessories Small Flange](https://m.media-amazon.com/images/I/41+LaSjm1QL.jpg)**21mm Flange Maymom Pump Parts Compatible with Spectra S2 S1 9 Plus Breastpump Not Original Spectra S2 S1 Replacement Pump Parts Accessories Small Flange**Maymom**$30.41**4.6★**— 9%**](https://www.amazon.com/dp/B07X8FDMMV) [![Maymom 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Replacment Pump Parts Not Original Spectra Flange Duckbill Valve](https://m.media-amazon.com/images/I/41-UdS8uYwL.jpg)**Maymom 21mm Flange and Duckbill Valve Compatible with Spectra S1 S2 9 Plus Replacment Pump Parts Not Original Spectra Flange Duckbill Valve**Maymom**$18.80**4.6★**— 6%**](https://www.amazon.com/dp/B0863NBHRX)

**~~View all trending →~~**

## **Demand & seasonality**

Weekly Amazon search volume, last 104 weeks — -8.9% search growth over the last 90 days.

400300Prime Day '24Spike '25Spike '26 seasonSepDecMarJunAugNovMarMay

No pronounced peak months · busiest ÷ quietest = 1.3×

## **Reviews**

What buyers praise and complain about, mined from review topics.

### **What buyers love **

**Size-Overall**33%

*“True to size”*

**Quality-Overall**20%

*“Amazing quality flanges”*

**Advertised Vs Actual Product**10%

*“way better than I expected”*

**Compatibility-Overall**7%

*“Good quality and truly is compatible”*

**Ease Of Cleaning**5%

*“Easy to clean”*

**Comfort-Overall**4%

*“Better fit, less discomfort, and a much more positive experience overall”*

**Durability**4%

*“So far these have held up great after 10 months with the exception of replacing the duckbills when needed”*

**Ease Of Use**3%

*“easy to use”*

**Washability**2%

*“being able to wash dishes a little less allows for more time spent elsewhere”*

**Value For Money**2%

*“Very affordable”*

### **What buyers complain about **

**Size-Overall**23%

*“they seem tiny”*

**Functionality-Overall**19%

*“they don't do a great job”*

**Quality-Overall**11%

*“Poor quality”*

**Leak-Proof**9%

*“Flawed, possibility of getting used product”*

**Compatibility-Overall**6%

*“Dont fit in the cup caddy for s2”*

**Breastfeeding Friendly**6%

*“Im not even getting a half ounce when I usually pump 4 to 6 ounces with each breast”*

**Durability**6%

*“Broke after the first use”*

**Ease Of Use**3%

*“Frustrating to Use”*

**Connectivity-Overall**3%

*“just deal with the connection issue”*

**Comfort-Overall**3%

*“Shield Edges Uncomfortable/Painful”*

### **Top return reasons **

**Size-Overall**77%

**Width**5%

**Defective Material/Parts**4%

**Functionality-Overall**4%

**Advertised Vs Actual Product**3%

**Leak-Proof**1%

**Compatibility-Overall**1%

**Breastfeeding Friendly**1%

**Value For Money**1%

**Product Condition**1%