FAQ · Power
18650 vs 21700 — which should I buy?
Buy the cell your light takes; they are not interchangeable. If you are choosing a light, a 21700 holds roughly 30–50% more capacity for meaningfully longer runtime and higher sustained output, at the cost of a slightly fatter body. An 18650 light carries a touch slimmer. For most people the extra runtime of a 21700 is worth the girth.
Related questions
Reader favorites
The short list — full rankings live on the best-gear page.
OLIGHT Warrior Ultra Rechargeable Tactical Flashlight Navy Blue
$97.99
Check price- Check price
HOTOR Travel Backpack (TSA-friendly carry-on)
LEATHERMAN Signal 19-in-1 Multi-Tool
$149.95
Check price
Straight disclosure —some links on this page are affiliate links. If you buy through them we may earn a commission from the retailer or network (such as CJ, Awin, Impact, or eBay Partner Network), at no extra cost to you. It never changes the price you pay, and it never changes a verdict.
66 guides published
57 products vetted
Featured merch
Original graphics, made to order. Gear-room aesthetics, no logos shouting.
