3/8 check valve
Skip itA small market ($61K/yr) — this niche doesn't clear our bar today.
Conversion
Great7.5%search→purchase rate — share of searches ending in a sale
Price range
Good$6.18–$34.84cheapest to priciest tracked listing — scored on the share inside $15–$100
Quality gap
Good4.3★avg incumbent rating — lower means beatable quality
Review moat
Good864.17avg incumbent reviews — the moat a new listing must climb
Returns
Good2.4%return rate — above 6% kills the launch gate
Avg price
Good$13.41avg listing price — sweet spot $15–$100
Competition
Okay65%top-5 click share — leaders hold, buyers still browse
Brand share
Okay85%top-5 brand share — brands hold most of the demand
Growth
Okay+6.3%90-day search growth — must beat 0% to launch
Market size
Bad$61K$61K/yr · 60K searches
Competition
The top 5 products take 65% of clicks — established leaders, but buyers still shop beyond them.Brands
11 falling
Sellers
42
Top-5 brand share
85%
Open market
12%
- EVIL ENERGY55%
- mxuteuk10%
- Litoexpe9%
- Tandefio7%
- BBTUS3%
- ChillWaves3%
- Open — no brand owns it (5 brands, 12%)
Product shelf
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 18 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
EVIL ENERGY 3/8 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Black (10mm OD 2PCS)
EVIL ENERGY$13.034.5★3,115 rev
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
Litoexpe$6.184.1★254 rev
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
mxuteuk$9.044.4★396 rev
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
Tandefio$10.184.1★140 rev
EVIL ENERGY 5/16 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Silver (8mm OD 2PCS)
EVIL ENERGY$9.984.5★3,115 rev
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
mxuteuk$9.68396 rev
EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Silver
EVIL ENERGY$13.3343 rev
EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Black
EVIL ENERGY$13.8643 rev
GASHER 1Pc One-Way Non-return Check Valve 3/8 Male x 3/8 Female Thread Prevent Water Back-flow
GASHER$10.2415 rev
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)
ChillWaves$16.18122 rev
Trending
90-day click momentummxuteuk 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
mxuteuk$9.684.4★
EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Silver
EVIL ENERGY$13.334.4★
GASHER 1Pc One-Way Non-return Check Valve 3/8 Male x 3/8 Female Thread Prevent Water Back-flow
GASHER$10.244.4★
EVIL ENERGY 5/16 Fuel Check Valve One Way Inline Non Return Diesel Gasoline Black (8mm OD 2PCS)
EVIL ENERGY$10.624.5★
EVIL ENERGY 3/8 (10mm) Check Valve 2 Pcs Aluminum One Way Fuel Check Valve for Gasoline Diesel & Coolant with Universal Hose Clamps Black
EVIL ENERGY$13.864.4★
Demand
Weekly Amazon search volume, last 14 weeks — +6.3% search growth over the last 90 days.Reviews
What buyers praise and complain about, mined from review topics.What buyers love
“great variety”
“works as it should”
“Good check valve”
“But theyre cheap”
“Does the job”
“The coffee maker is now working perfectly again”
“fit”
“No leaks”
“Easy to install”
“are made of high quality aluminum”
What buyers complain about
“both of them leak after building pressure”
“Doesnt hold pressure”
“Too cheap”
“they are still not working”
“when i beat one it cracked”
“3/8 hose is too large for these”
“blocks fuel flow”
“not lots of margin for error Working for over a months so far”
“Not robust”
“Wasted $33.31 for this”