string line
Worth a lookShows low returns (0.3%), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.
Returns
Incredible0.3%return rate — above 5% kills the launch gate
Conversion
Incredible12.0%search→purchase rate — share of searches ending in a sale
Review moat
Good784.71avg incumbent reviews — the moat a new listing must climb
Brand share
Good65%top-5 brand share — brands hold most of the demand
Quality gap
Good4.4★avg incumbent rating — lower means beatable quality
Competition
Okay55%top-5 click share — leaders hold, buyers still browse
Market size
Okay£206K£206K/yr · 215K searches
Price range
Okay£2.74–£22.68cheapest to priciest tracked listing — scored on the share inside $15–$100
Growth
Okay+3.9%90-day search growth — must beat 0% to launch
Avg price
Bad£7.95avg listing price — sweet spot $15–$100
According to Flapen's Amazon United Kingdom niche tracking, string line is a £206K/yr Amazon United Kingdom market (215K searches/yr). The top 5 brands hold 65% of demand. Demand peaks in Mar–Apr–May. Verdict: Worth a look — 56/100.
Data updated Jul 22, 2026 · scored weekly · How we score niches
string line market data
- Units sold / yr
- 20K–25K
- avg 750–1,000/product
- Revenue / yr
- £159K–£199K
- units × avg price
- Conversion rate
- 12.0%
- Avg BSR
- #281
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 43%
- Out of stock
- 1.7%
- Avg brand age
- 72 months
- Avg seller age
- 165 days
Competition & brand share
The top 5 products take 55% of clicks — established leaders, but buyers still shop beyond them.Brands
15 falling
Sellers
83
Top-5 brand share
65%
Top 20: 100%
Top-5 click share
55%
Top 20: 99%
Open market
26%
- tenn well16%
- Rolson14%
- OX Tools12%
- Spear & Jackson11%
- Blue Spot Tools11%
- Tracer9%
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — +3.9% search growth over the last 90 days.Peak months: Mar, Apr, May · busiest ÷ quietest = 2.3×
Top string line search terms
- string line110K/yr
- builders line25K/yr
- brick line33K/yr
- builders string line11K/yr
- bricklayers line13K/yr
- bricklaying line16K/yr
- stringline4K/yr
- builders string4K/yr
Top string line products on Amazon
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 21 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Rolson 52606 Brick Line 100 m Green
Rolson£4.174.2★1,273 rev
Spear & Jackson 10505Z Line and Pins
Spear & Jackson£7.724.4★926 rev
OX Pro Nylon High Vis Builders Line 105m / 350ft - Cyan
OX Tools£6.774.2★1,403 rev
Green 328 Feet Mason Line Braided Brick Line for Building Gardening Marking and DIY Projects
tenn well£5.504.3★743 rev
Tracer 100m String Line Anti-Tangle Hi-Vis Builders & Bricklaying Line
Tracer£10.274.5★162 rev
Newest
by launch date
Grettz 100m 8 Braid Green Stringline with Weatherproof Anti-Tangle Reel High Visibility Builders String Line for Bricklaying Landscaping & Construction
Grettz£8.4163 rev
Grettz 100 m Heavy-Duty 8-Braid Nylon Stringline High-Visibility Yellow Bricklaying & Landscaping Line for Masonry Construction & DIY Projects
Grettz£8.3119 rev
Dekton 100m Brick Line with Holder | High-Visibility 100m Masonry String | Plastic Spindle Handle & Lock | Ideal for Bricklaying & Construction Work
DEKTON£5.1115 rev
OX Trade 30m/100 ABS Chalk Reel w/Grip Value Pack - Standard Bold Line / 6:1 Gear Ratio
OX Tools£9.60260 rev
Tracer 100m String Line Anti-Tangle Hi-Vis Builders & Bricklaying Line
Tracer£10.27162 rev
Trending
90-day click momentum
Orange 328 Feet Bricklaying Line Braided Brick Builders Line Strong String Line for Building Gardening Marking and DIY Projects
tenn well£5.834.3★
Draper 100m Orange Ranging Line | Polypropylene Rope on Spool | Bricklaying String | Garden Twine | Chalk Line | Builders Tool | 28821
Draper£5.474.6★
Dekton 100m Brick Line with Holder | High-Visibility 100m Masonry String | Plastic Spindle Handle & Lock | Ideal for Bricklaying & Construction Work
DEKTON£5.114.2★
Spear & Jackson 10505Z Line and Pins
Spear & Jackson£7.724.4★
Blue Spot 34638 82m Brick Line
Blue Spot Tools£4.704.5★
What buyers say about string line
What buyers praise and complain about, mined from review topics.What buyers love
“Excellent Product”
“Good product in good price”
“Easy to use”
“Nice apart from the colour”
“Exactly as described”
“Works well”
“Made of quality material”
“Bright”
“Strong and visual”
“durable”
What buyers complain about
“Poor quality control prior to shipping”
“Broke first use”
“Thin”
“The plastic has a cheap feel”
“so pale in colour that you can't see it”
“Not fit for purpose”
“it doesn't adhere to anything”
“Didnt get any instructions with this”
“a little frustrating at times”
Top return reasons
Common questions
- Is string line profitable to sell on Amazon United Kingdom?
- The niche generates £206K/yr across 21 tracked products. 2 of 2 products launched in the last 360 days are still selling. 90-day search growth is +3.9%. Flapen's verdict: Worth a look (56/100).
- How competitive is the string line niche?
- 15 brands and 83 sellers compete. The top 5 products take 55% of clicks and top 5 brands hold 65% of demand.
- What do buyers complain about in string line?
- Top complaints mined from reviews: Quality-Overall, Durability, Thickness. The return rate is 0.3%.
- When does demand for string line peak?
- Demand peaks in Mar–Apr–May; the busiest month runs 2.3× the quietest.
- What does it cost to enter the string line niche?
- Listings span £2.74–£22.68; the average listing price is £7.95 (sweet spot $15–$100). The average incumbent carries 785 reviews — the moat a new listing must climb.