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refractometer saltwater aquarium
Skip itA concentrated shelf (top 5 take 93% of clicks) — this niche doesn't clear our bar today.
Conversion
Great11.1%search→purchase rate — share of searches ending in a sale
Price range
Great$13.37–$48.86cheapest to priciest tracked listing — scored on the share inside $15–$100
Avg price
Great$20.49avg listing price — sweet spot $15–$100
Review moat
Good1,247.86avg incumbent reviews — the moat a new listing must climb
Returns
Good2.9%return rate — above 6% kills the launch gate
Quality gap
Good4.4★avg incumbent rating — lower means beatable quality
Growth
Bad-11.3%90-day search growth — must beat 0% to launch
Brand share
Bad93%top-5 brand share — brand-locked demand
Market size
Bad$54K$54K/yr · 24K searches
Competition
Bad93%top-5 click share — a locked-up shelf