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napa 4003 fuel filter

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Soft demand (-36.0% this quarter) — this niche doesn't clear our bar today.

Market size 45Growth 7Conversion 20Competition 20Returns 100Price range 95Avg price 93Brand share 14Review moat 100Quality gap 96

Review moat

Incredible7.25

avg incumbent reviews — the moat a new listing must climb

Returns

Incredible0.0%

return rate — above 6% kills the launch gate

Quality gap

Incredible3.9★

avg incumbent rating — lower means beatable quality

Price range

Incredible$27.97–$71.00

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

Avg price

Great$51.52

avg listing price — sweet spot $15–$100

Market size

Okay$243K

$243K/yr · 300K searches

Conversion

Bad1.6%

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

Competition

Bad76%

top-5 click share — a locked-up shelf

Brand share

Bad94%

top-5 brand share — brand-locked demand

Growth

Bad-36.0%

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

Competition

The top 5 products capture 76% of clicks — a locked-up shelf that new listings rarely crack.

Brands

7 falling

Sellers

39

Top-5 brand share

94%

Open market

2%

  • linenb31%
  • Topzywlc29%
  • TrixmEsque14%
  • Generic11%
  • LOKLNEYK9%
  • Skluauat4%
  • Open — no brand owns it (1 brand, 2%)

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%$24K20%$49K30%$73K40%$97K110100 Reviews — right = deep review moat Market 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.

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -36.0% search growth over the last 90 days.
9K7KSpike '24Holiday '24Prime Day '25Spike '25Spike '26SepDecMarJunAugNovMarMay

Peak months: Jan, Feb, Dec · busiest ÷ quietest = 2.4×

Reviews

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

What buyers love

Quality-Overall32%

“Great product, just as advertised”

Advertised Vs Actual Product14%

“Works as it should”

Ease Of Cleaning10%

“Simple twist-on design making the whole process much cleaner and more efficient”

Value For Money8%

“Maybe a lower price lol would be wonderfully appreciated”

Fuel Efficiency8%

“After the ATF kicks yours in”

Size-Overall6%

“Fits perfectly”

Motor Power6%

“Almost like Hiram Percy Maxim designed it for a 30cc engine himself”

Filtration5%

“Its a inline filter that works pretty well”

Design-Overall3%

“Perfect design and works really well, easy to clean, not sure why others rated it poorly,”

Assembly/Installation3%

“Worked great and easy to install”

What buyers complain about

Leak-Proof25%

“Leaking junk”

Quality-Overall19%

“Garbage”

Noise Level19%

“My neighbors are constantly complaining about the noise these little nitro engines make, so I machined a slip coupler with a 1/2-28 thread and voilà”

Material Quality13%

“Also the endcaps are cheap plastic”

Advertised Vs Actual Product13%

“This is not what is advertised DO NOT BUY THIS”

Functionality-Overall6%

“Does not work at all”

Top return reasons

Filtration33%
Advertised Vs Actual Product30%
Functionality-Overall10%
Compatibility-Overall5%
Size-Overall5%
Defective Material/Parts5%
Value For Money5%
Quality-Overall3%
Material Quality3%
Durability3%