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21mm ソケット

21mm ソケット shows low returns (0.7%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.

Flapen Score

57
Worth a look

Ranks 2,057 of 4,191 DIY・工具・ガーデン niches · on the category median

Market size 95Growth 3Conversion 72Competition 68Returns 97Price range 0Avg price 0Brand share 50Review moat 75Quality gap 67
This niche Category average · 4,191 niches

Is 21mm ソケット profitable on Amazon?

According to Flapen's Amazon Japan niche tracking, 21mm ソケット is a ¥2.0M/yr Amazon Japan market (29K searches/yr). The top 5 brands hold 75% of demand. Demand peaks in Apr–Nov–Dec. Verdict: Worth a look — 57/100.

21mm ソケット: the Amazon niche in one read

Everything a seller checks before entering, in three answers.

Is the demand real?

Worth a look. Search demand moved -44.1% over the last 90 days and 6.6% of searches end in a purchase.

¥2.0M

revenue / yr

Units sold / yr2K
Search volume / yr-44.1%29K
Conversion rate6.6%
Avg price¥1065.81

Who owns the niche?

The top 5 brands hold 75% of demand, so 25% of the market is open.

25%

open market share

Brands · sellers16 · 87
Top-5 product click share44%
Open market25%
Avg brand age91 months

Is there a way in?

Listing quality. The average product page scores 0/100 on content standards. Incumbents average 4.3★ — the gap to enter on.

0/100

page quality · 29 products

Sponsored placement48%
New entrants (1y)1· 1 succeeded
Avg rating4.3★
Avg reviews515

Top 21mm ソケット products & what they sell for

Every tracked product — its share of the shelf, its review moat, and what it sells for.

Competition: brands, sellers & click share

The top 5 products take 44% of clicks — established leaders, but buyers still shop beyond them.

¥0¥81K¥161K¥242K¥323K101001K10K Review Count Sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

Brands

16 falling

Sellers

87

Top-5 brand share

75%

Top 20: 100%

Top-5 click share

44%

Top 20: 92%

Open market

25%

  • トネ(TONE)32%
  • エーモン(amon)12%
  • ベッセル(VESSEL)8%
  • タジマ8%
  • WORKPRO7%
  • 京都機械工具(KTC)7%

21mm ソケット demand & seasonality

Weekly search volume, with the niche's key stats alongside.

Volume29KCVR6.6%Products29Brands16Top 5 Brands75%OOS Rate0.0%Rating4.3★Reviews515Avg BSR#33
1K750Spike '24Holiday '24Spike '25Prime Day '25Holiday '25Spike '26SepDecMarJunAugNovMarMay

Peak months: Apr, Nov, Dec · busiest ÷ quietest = 4.7×

Top 21mm ソケット search terms shoppers use

The exact queries shoppers type, with yearly volume, growth and conversion.

  • 21mm ソケット11K/yr
  • インパクト ソケット 21mm6K/yr
  • 21ソケット3K/yr
  • ソケット 21mm4K/yr
  • 21mm ソケット インパクト4K/yr

What reviews say buyers love and hate about 21mm ソケット

What buyers mention most, as a share of all reviews.

What buyers love

81% of reviews
使用の容易さ30%

使えます

コストパフォーマンス23%

価格の信頼性

総合品質9%

さすがコーケンのクオリティ

耐久性5%

トネのインパクト用ソケットが1番長持ちしています、毎日使用するので2年位でガダが来ますけど、多い時は1日で20台位取って付けてを繰り返すので耐久性はいいと思います。

サイズ全体3%

ジャストサイズ

What buyers complain about

69% of reviews
耐久性20%

壊れた。

総合品質12%

ただのゴミ以下

使用の容易さ6%

ちょっと使いづらいかも...

厚み6%

薄くはない

生锈/腐食する6%

錆びてこないか少し心配です。

21mm ソケット return rate & reasons

Why buyers send it back, as a share of all return requests.

0.7%

Return rate

0%

Fixable by listing

The "fixable" share counts expectation-mismatch reasons — size, look, advertised-vs-actual — that better copy and images address.

1サイズ全体
22%
2メカニズムの問題
11%
3不良材料/部品
10%
4機能全体
7%
5使用の容易さ
5%

Common 21mm ソケット questions

The questions sellers ask about this niche, answered from the tracked metrics.

Flapen scores 21mm ソケット 57/100 on Amazon Japan — Worth a look. The niche generates ¥2.0M/yr across 29 tracked products. 1 of 1 products launched in the last 360 days are still selling. Search demand moved -44.1% over the last 90 days.
Search demand for 21mm ソケット on Amazon Japan peaks in Apr–Nov–Dec, where the busiest month runs 4.7× the quietest.