---
title: "Reviews — 4 inch air filter - Flapen"
canonical_url: "https://flapen.com/research/us/automotive/4-inch-air-filter/reviews"
last_updated: "2026-08-09T20:02:01.858Z"
locale: en
meta:
  description: "Niche score 53/100 · $89K/yr market · 61K searches/yr · $32.07 avg price. A small market ($89K/yr) keeps it on the watch list. Data updated Jul 2026."
  "og:description": "Niche score 53/100 · $89K/yr market · 61K searches/yr · $32.07 avg price. A small market ($89K/yr) keeps it on the watch list. Data updated Jul 2026."
  "og:title": "Reviews — 4 inch air filter - Flapen"
---

# **4 inch air filter**

**Worth a look**

Shows a sweet-spot price point ($32.07 avg), but a small market ($89K/yr) keeps it on the watch list.

Market size 22Growth 22Conversion 55Competition 73Returns 75Price range 87Avg price 95Brand share 59Review moat 64Quality gap 38

**Avg price**

**Incredible****$32.07**

avg listing price — sweet spot $15–$100

**Price range**

**Great****$9.57–$65.39**

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

**Returns**

**Great****2.0%**

return rate — above 5% kills the launch gate

**Competition**

**Good****41%**

top-5 click share — leaders hold, buyers still browse

**Review moat**

**Good****940.71**

avg incumbent reviews — the moat a new listing must climb

**Brand share**

**Good****70%**

top-5 brand share — brands hold most of the demand

**Conversion**

**Good****4.6%**

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

**Quality gap**

**Okay****4.5★**

avg incumbent rating — lower means beatable quality

**Market size**

**Bad****$89K**

$89K/yr · 61K searches

**Growth**

**Bad****-6.9%**

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

## Reviews