---
title: "spectra flange 21mm — Niche Verdict: Skip it (42/100) | Amazon United States - Flapen"
canonical_url: "https://flapen.com/amazon/research/us/baby-products/spectra-flange-21mm"
last_updated: "2026-07-13T22:45:44.576Z"
locale: en
meta:
  description: "a concentrated shelf (top 5 take 78% of clicks) — spectra flange 21mm doesn't clear our bar today."
  "og:description": "a concentrated shelf (top 5 take 78% of clicks) — spectra flange 21mm doesn't clear our bar today."
  "og:title": "spectra flange 21mm — Niche Verdict: Skip it (42/100) | Amazon United States - Flapen"
---

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# **spectra flange 21mm**

**Skip it**

A concentrated shelf (top 5 take 78% of clicks) — this niche doesn't clear our bar today.

Market size 54Growth 19Conversion 98Competition 18Returns 25Price range 71Avg price 77Brand share 22Review moat 39Quality gap 40

**Conversion**

**Incredible****17.0%**

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

**Avg price**

**Great****$15.66**

avg listing price — sweet spot $15–$100

**Price range**

**Good****$7.97–$32.51**

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

**Market size**

**Good****$359K**

$359K/yr · 135K searches

**Quality gap**

**Okay****4.5★**

avg incumbent rating — lower means beatable quality

**Review moat**

**Okay****2,565.92**

avg incumbent reviews — the moat a new listing must climb

**Returns**

**Okay****6.0%**

return rate — above 6% kills the launch gate

**Brand share**

**Bad****91%**

top-5 brand share — brand-locked demand

**Growth**

**Bad****-11.5%**

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

**Competition**

**Bad****78%**

top-5 click share — a locked-up shelf

## **Competition**

The top 5 products capture 78% of clicks — a locked-up shelf that new listings rarely crack.

**Brands**

**9 **▲rising

**Sellers**

**18**

**Top-5 brand share**

**91%**

**Open market**

**6%**

- Maymom51% - Momstouch16% - Hranio13% - Suniceme8% - PUMPMOM-US4% - MilkFlow3% - Open — no brand owns it (3 brands, 6%)

## **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%$36K20%$72K30%$108K40%$144K101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales

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

All 12 tracked products in this niche — three views at once, no toggling.

### **Top sellers**

by 90-day click share

[1![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) [2![Hranio Breast Pump Parts Compatible with 21mm Spectra Flange 21mm Spectra Replacement Pump Parts s1 s2 (Flange 21mm 2 Pcs)](https://m.media-amazon.com/images/I/41ezYMeTi+L.jpg)**Hranio Breast Pump Parts Compatible with 21mm Spectra Flange 21mm Spectra Replacement Pump Parts s1 s2 (Flange 21mm 2 Pcs)**Hranio**$9.80**4.5★217 rev](https://www.amazon.com/dp/B0D93LMZS7) [3![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) [4![Maymom Wide Neck Pump Part for Spectra S1/S2 Pumps; Incl Wide Mouth Flange; Not Original Spectra Flange; Replaces Spectra Shield (21 mm Two Flanges)](https://m.media-amazon.com/images/I/41uUBorLO2L.jpg)**Maymom Wide Neck Pump Part for Spectra S1/S2 Pumps; Incl Wide Mouth Flange; Not Original Spectra Flange; Replaces Spectra Shield (21 mm Two Flanges)**Maymom**$16.55**4.7★7,932 rev](https://www.amazon.com/dp/B078PJPLXL) [5![Flange Inserts 21mm Compatible with Medela/Spectra/TSRETE/Elvie/Momcozy/Bellababy Breast Pump 24mm Shields/Flanges Reduce 24mm Nipple Tunnel Down to 21 mm 4PCS](https://m.media-amazon.com/images/I/31bhFe+EYtL.jpg)**Flange Inserts 21mm Compatible with Medela/Spectra/TSRETE/Elvie/Momcozy/Bellababy Breast Pump 24mm Shields/Flanges Reduce 24mm Nipple Tunnel Down to 21 mm 4PCS**Suniceme**$7.97**4.5★971 rev](https://www.amazon.com/dp/B0CW1VDP9D)

**~~View all top sellers →~~**

### **Newest**

by launch date

[![21mm Flange and Duckbill Valve for S1/S2/9+ Flange Inserts for Spectra Replacement Pump Parts (2-Pack) - Not Original Spectra Accessories](https://m.media-amazon.com/images/I/41QnObriiwL.jpg)**21mm Flange and Duckbill Valve for S1/S2/9+ Flange Inserts for Spectra Replacement Pump Parts (2-Pack) - Not Original Spectra Accessories**MilkFlow**$11.18**75 rev1y ago](https://www.amazon.com/dp/B0FCSWCX3N) [![BALIME 21MM Wide-Mouth Flange Spectra Replacement Pump Parts for S1 S2 - BPA Free Spectra Replacement Pump Parts - Perfect for Travel & Working Moms (2-Pack)](https://m.media-amazon.com/images/I/31-Iyz+A1YL.jpg)**BALIME 21MM Wide-Mouth Flange Spectra Replacement Pump Parts for S1 S2 - BPA Free Spectra Replacement Pump Parts - Perfect for Travel & Working Moms (2-Pack)**BALIME**$8.22**129 rev1y ago](https://www.amazon.com/dp/B0DXTF63LS) [![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) [![Hranio Breast Pump Parts Compatible with 21mm Spectra Flange 21mm Spectra Replacement Pump Parts s1 s2 (Flange 21mm 2 Pcs)](https://m.media-amazon.com/images/I/41ezYMeTi+L.jpg)**Hranio Breast Pump Parts Compatible with 21mm Spectra Flange 21mm Spectra Replacement Pump Parts s1 s2 (Flange 21mm 2 Pcs)**Hranio**$9.80**217 rev2y ago](https://www.amazon.com/dp/B0D93LMZS7) [![Flange Inserts 21mm Compatible with Medela/Spectra/TSRETE/Elvie/Momcozy/Bellababy Breast Pump 24mm Shields/Flanges Reduce 24mm Nipple Tunnel Down to 21 mm 4PCS](https://m.media-amazon.com/images/I/31bhFe+EYtL.jpg)**Flange Inserts 21mm Compatible with Medela/Spectra/TSRETE/Elvie/Momcozy/Bellababy Breast Pump 24mm Shields/Flanges Reduce 24mm Nipple Tunnel Down to 21 mm 4PCS**Suniceme**$7.97**971 rev2y ago](https://www.amazon.com/dp/B0CW1VDP9D)

**~~View all new products →~~**

### **Trending**

90-day click momentum

[![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★**▲ 232%**](https://www.amazon.com/dp/B0DNQ49L24) [![BALIME 21MM Wide-Mouth Flange Spectra Replacement Pump Parts for S1 S2 - BPA Free Spectra Replacement Pump Parts - Perfect for Travel & Working Moms (2-Pack)](https://m.media-amazon.com/images/I/31-Iyz+A1YL.jpg)**BALIME 21MM Wide-Mouth Flange Spectra Replacement Pump Parts for S1 S2 - BPA Free Spectra Replacement Pump Parts - Perfect for Travel & Working Moms (2-Pack)**BALIME**$8.22**4.4★**▲ 145%**](https://www.amazon.com/dp/B0DXTF63LS) [![21mm Flange and Duckbill Valve for S1/S2/9+ Flange Inserts for Spectra Replacement Pump Parts (2-Pack) - Not Original Spectra Accessories](https://m.media-amazon.com/images/I/41QnObriiwL.jpg)**21mm Flange and Duckbill Valve for S1/S2/9+ Flange Inserts for Spectra Replacement Pump Parts (2-Pack) - Not Original Spectra Accessories**MilkFlow**$11.18**4.3★**▲ 114%**](https://www.amazon.com/dp/B0FCSWCX3N) [![Maymom Wide Neck Pump Part for Spectra S1/S2 Pumps; Incl Wide Mouth Flange; Not Original Spectra Flange; Replaces Spectra Shield (21 mm Two Flanges)](https://m.media-amazon.com/images/I/41uUBorLO2L.jpg)**Maymom Wide Neck Pump Part for Spectra S1/S2 Pumps; Incl Wide Mouth Flange; Not Original Spectra Flange; Replaces Spectra Shield (21 mm Two Flanges)**Maymom**$16.55**4.7★**▲ 50%**](https://www.amazon.com/dp/B078PJPLXL) [![Momstouch 21mm Flange Compatible with Spectra S1 S2 9 Plus Synergy Gold Breastpump Replacement to Spectra Pump Parts and Flange; Not Original; Replaces Shield](https://m.media-amazon.com/images/I/31KLKQnVfFL.jpg)**Momstouch 21mm Flange Compatible with Spectra S1 S2 9 Plus Synergy Gold Breastpump Replacement to Spectra Pump Parts and Flange; Not Original; Replaces Shield**Momstouch**$15.66**4.6★**▲ 49%**](https://www.amazon.com/dp/B0CM61MNDH)

**~~View all trending →~~**

## **Demand & seasonality**

Weekly Amazon search volume, last 104 weeks — -11.5% search growth over the last 90 days.

4K3K seasonSepDecMarJunAugNovMarMay

No pronounced peak months · busiest ÷ quietest = 1.2×

## **Reviews**

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

### **What buyers love **

**Size-Overall**31%

*“fit my pump no problem”*

**Quality-Overall**12%

*“Amazing quality flanges”*

**Advertised Vs Actual Product**9%

*“Exactly what I needed”*

**Comfort-Overall**7%

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

**Breastfeeding Friendly**6%

*“Works great with my Spectra breast pump”*

**Ease Of Cleaning**6%

*“Easy to clean”*

**Compatibility-Overall**5%

*“Good quality and truly is compatible”*

**Value For Money**5%

*“Very affordable”*

**Ease Of Use**3%

*“easy to use”*

**Durability**3%

*“Its durable and easy to wash and sterilize”*

### **What buyers complain about **

**Size-Overall**26%

*“they seem tiny”*

**Quality-Overall**13%

*“Absolutely Garbage”*

**Functionality-Overall**13%

*“Works but not too well”*

**Comfort-Overall**8%

*“Not comfortable”*

**Hard Feel**7%

*“the material is not as soft”*

**Skin Health**4%

*“Skin Shredder”*

**Breastfeeding Friendly**4%

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

**Leak-Proof**3%

*“They have poor fit which causes discomfort and leaking”*

**Ease Of Use**3%

*“It makes the arduous”*

**Value For Money**2%

*“You can see why these are cheaper in person”*

### **Top return reasons **

**Size-Overall**77%

**Width**6%

**Functionality-Overall**4%

**Advertised Vs Actual Product**3%

**Defective Material/Parts**3%

**Material Quality**1%

**Value For Money**1%

**Compatibility-Overall**1%

**Breastfeeding Friendly**1%

**Leak-Proof**1%