---
title: "Trend — 21v lithium ion battery - Flapen"
canonical_url: "https://flapen.com/research/us/tools-home-improvement/21v-lithium-ion-battery/trend"
last_updated: "2026-08-08T15:56:01.799Z"
locale: en
meta:
  description: "Niche score 50/100 · $73K/yr market · 96K searches/yr · $29.19 avg price. A small market ($73K/yr) keeps it on the watch list. Data updated Jul 2026."
  "og:description": "Niche score 50/100 · $73K/yr market · 96K searches/yr · $29.19 avg price. A small market ($73K/yr) keeps it on the watch list. Data updated Jul 2026."
  "og:title": "Trend — 21v lithium ion battery - Flapen"
---

# **21v lithium ion battery**

**Worth a look**

Shows a thin review moat (94 avg reviews), but a small market ($73K/yr) keeps it on the watch list.

Market size 18Growth 48Conversion 33Competition 50Returns 33Price range 95Avg price 95Brand share 56Review moat 95Quality gap 62

**Review moat**

**Incredible****94.33**

avg incumbent reviews — the moat a new listing must climb

**Avg price**

**Incredible****$29.19**

avg listing price — sweet spot $15–$100

**Price range**

**Incredible****$17.91–$47.70**

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

**Quality gap**

**Good****4.4★**

avg incumbent rating — lower means beatable quality

**Brand share**

**Good****71%**

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

**Competition**

**Good****55%**

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

**Growth**

**Okay****+18.6%**

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

**Conversion**

**Okay****2.6%**

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

**Returns**

**Okay****4.4%**

return rate — above 5% kills the launch gate

**Market size**

**Bad****$73K**

$73K/yr · 96K searches

**Signals**[** Low Review Barrier**](https://flapen.com/research/niches?market=us&signal=low_review_barrier "Top brand's reviews < 500") [** Out of Stock**](https://flapen.com/research/niches?market=us&signal=out_of_stock "OOS rate > 10%")

## Trend