3/8 Check Valve
FailShoppers spend an estimated $61K a year here, so 3/8 Check Valve is a Fail.
- Flapen Score
- 46 / 100Ranks 4,486 of 7,287 Automotive niches · −3 vs the category median of 4946
- Market size
- $61K/yr60K searches / yr
- 90-day growth
- +6.3%search demand this quarter
- Competition
- 65%top-5 click share · 11 brands · 42 sellers
Flapen Score
3/8 Check Valve against its category
The dotted line is the Automotive average. Past it, 3/8 Check Valve is stronger. Inside it, weaker.
Market
The 3/8 Check Valve market on Amazon at a glance
Shoppers on Amazon United States searched for 3/8 Check Valve 60K times last year and spent an estimated $61K. The top 5 brands take 85% of clicks. Flapen scores it 46 out of 100, a Fail.
01 · Demand
An estimated 7.5% of those searches ended in a purchase.
Shoppers searched for this 60K times in the last 12 months. That counts every search on Amazon United States for this niche's terms. An estimated 7.5% of those searches ended in a purchase. Searches in the last 90 days moved +6.3% against the 90 days before. Searches, conversion and average price together put the market at an estimated $61K a year.
- Searches, last 12 months
- 60K
- Growth, 90 days vs prior 90
- +6.3%
- Conversion, latest week
- 7.5%
- Market size, estimated
- $61Ka year
- Top search term
- 3/8 check valve20K searches a year
02 · Price
A sale here is worth $13.41.
Listings sell for $13.41 on average, from $6.18 to $34.84. Amazon reports units sold in ranges. This niche sold 5K to 6K a year. The average listing sells 250 to 500 of them. At $13.41 that is $3K to $7K a year per listing.
- Average price
- $13.41under the $15 to $100 sweet spot
- Price range
- $6.18–$34.84
- Amazon United States median price
- $24.38across 115,062 niches
- Units sold a year
- 5K–6K
- Units per listing a year
- 250–500
- Revenue per listing a year
- $3K–$7K
- Returns
- 2.4%of orders · Amazon United States median 2.1%
03 · Entry bar
The bar here is ads.
100% of listings pay for placement with sponsored ads. 100% ship with Prime. On an average day, 0.0% of listings are out of stock. The average listing ranks #126 within Exhaust & Emissions. It carries 864 reviews at 4.35 stars, so a new listing needs social proof before a better product.
- Sponsored listings
- 100%
- Prime listings
- 100%
- Out of stock, average day
- 0.0%
- Average rank
- #126in Exhaust & Emissions
- Average rating
- 4.35 starsAmazon United States average 4.42 stars
- Average reviews
- 864per listing
- Listings tracked
- 18
04 · Newcomers
0 of last year's 4 launches cleared the first-year sales bar.
4 products launched here in the last 12 months. 0 of them cleared the first-year sales bar, our mark for a successful launch. The brands on the shelf have sold for 45 months on average, so the names here are settling in.
- Launched, last 12 months
- 4
- Successful launches
- 0Amazon's first-year sales bar
- Average brand age
- 45 months
Products
Top 3/8 Check Valve products & what they sell for
The products selling here, as shoppers see them on Amazon. Shelf share and sales are our estimates.
Prices and ratings read from Amazon on Jul 9, 2026. The live listing can differ.
Top sellers
by estimated 90-day click share
EVIL ENERGY 3/8 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Black (10mm OD 2PCS)
- Price
- $13.03
- Rating
- 4.5/5
- Reviews
- 3,115
- Age
- 5y ago

Litoexpe 3/8 One Way Inline Check Valve Non Return Ozone Resistance PVDF Plastic One-Way Fuel Oil Water Gas Pump Air Check Valve Pack of 2
- Price
- $6.18
- Rating
- 4.1/5
- Reviews
- 254
- Age
- 3y ago

mxuteuk 2Pcs 3/8 10mm Aluminium Silver Non Return One Way Check Valve with 4Pcs 6-12mm Universal Adjustable Hose Clamps for Fuel Petrol Diesel Line Oil M-H-032-10mm
- Price
- $9.04
- Rating
- 4.4/5
- Reviews
- 396
- Age
- 4y ago

Tandefio 4 Pcs 1/4 5/16 3/8 1/2 Fuel Non Return Inline One Way Check Valve for Fuel Line Oil Petrol Diesel Gasoline Water Aluminium Alloy Silver 6 mm 8 mm 10 mm 12 mm
- Price
- $10.18
- Rating
- 4.1/5
- Reviews
- 140
- Age
- 2y ago

EVIL ENERGY 5/16 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Silver (8mm OD 2PCS)
- Price
- $9.98
- Rating
- 4.5/5
- Reviews
- 3,115
- Age
- 6y ago
Trending
estimated 90-day click momentum
mxuteuk 2Pcs 3/8 10mm Aluminium Black Non Return One Way Check Valve with 4Pcs 6-12mm Universal Adjustable Hose Clamps for Fuel Petrol Diesel Line Oil
- Price
- $9.68
- Rating
- 4.4/5
- Reviews
- 396
- Age
- 6mo ago

EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Silver
- Price
- $13.33
- Rating
- 4.4/5
- Reviews
- 43
- Age
- 7mo ago

GASHER 1Pc One-Way Non-return Check Valve 3/8 Male x 3/8 Female Thread Prevent Water Back-flow
- Price
- $10.24
- Rating
- 4.4/5
- Reviews
- 15
- Age
- 9mo ago

EVIL ENERGY 5/16 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Black (8mm OD 2PCS)
- Price
- $10.62
- Rating
- 4.5/5
- Reviews
- 3,115
- Age
- 5y ago

EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Black
- Price
- $13.86
- Rating
- 4.4/5
- Reviews
- 43
- Age
- 8mo ago
Newest
by launch date
mxuteuk 2Pcs 3/8 10mm Aluminium Black Non Return One Way Check Valve with 4Pcs 6-12mm Universal Adjustable Hose Clamps for Fuel Petrol Diesel Line Oil
- Price
- $9.68
- Rating
- 4.4/5
- Reviews
- 396
- Age
- 6mo ago

EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Silver
- Price
- $13.33
- Rating
- 4.4/5
- Reviews
- 43
- Age
- 7mo ago

EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Black
- Price
- $13.86
- Rating
- 4.4/5
- Reviews
- 43
- Age
- 8mo ago

GASHER 1Pc One-Way Non-return Check Valve 3/8 Male x 3/8 Female Thread Prevent Water Back-flow
- Price
- $10.24
- Rating
- 4.4/5
- Reviews
- 15
- Age
- 9mo ago

ChillWaves 304 Stainless Steel In-Line Siamese Check Valve 3/8 NPT Male x 3/8 NPT Female Thread One-Way Non-return Check Valve for Backflow Prevention(1-PACK)
- Price
- $16.18
- Rating
- 4.3/5
- Reviews
- 122
- Age
- 1y ago
Competition
Competition: brands, sellers & click share
The top 5 products take an estimated 65% of clicks. Leaders hold, but buyers still shop past them.
Brands
11 falling
Sellers
42
Est. top-5 brand share
85%
Top 20: 100%
Est. top-5 click share
65%
Top 20: 100%
Open market
12%
- EVIL ENERGY55%
- mxuteuk10%
- Litoexpe9%
- Tandefio7%
- BBTUS3%
- ChillWaves3%
- Open — no brand owns it (5 brands, 12%)
Demand
3/8 Check Valve search demand
Weekly searches over the year. Pick a range.
Search terms
Top 3/8 Check Valve search terms shoppers use
The exact words shoppers type, with estimated yearly volume, growth, and conversion.
- 3/8 check valve20K/yr
- fuel line check valve13K/yr
- fuel check valve11K/yr
- 3/8 fuel check valve4K/yr
- fuel check valve 3/83K/yr
- 3/8 check valve water4K/yr
- one way fuel check valve2K/yr
- inline fuel check valve3K/yr
Reviews and returns
What reviews say buyers love and hate about 3/8 Check Valve
We read the reviews and the return reasons for every product selling here.
“both of them leak after building pressure”
Every topic
Every topic buyers talk about, one row each.
Red shows the share of negative reviews and green the share of positive reviews, biggest topic first. Open a row to read what they wrote.
17 topics
Keep looking
Related niches
Niches in the same category that score near this one. Research these next.
Best Flapen score
The highest-scoring niches we track right now, across every category.
FAQ
Common 3/8 Check Valve questions
Answered from the same tracked data.
Figures on this page are estimates modeled from public Amazon pages and third-party keyword data. Amazon does not supply them, and no connected seller's data is used. How we handle Amazon data









