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Coros APEX 4 (42mm) vs Flextail Zero Power 5k

Weight and specs compared for 2026 — and which one to choose.

Coros APEX 4 (42mm) is the lighter option — 29 g lighter than the Flextail Zero Power 5k (34% less weight). If grams matter to you, that is the one to beat.
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Spec Coros APEX 4 (42mm) Flextail Zero Power 5k
Weight 56 g · 0.056 kg · 0.12 lb 85 g · 0.085 kg · 0.19 lb
Brand Coros Flextail
Category Electronics Electronics
Coros APEX 4 (42mm)
56 g

Mountain sports GPS watch with dual-frequency satellite positioning for improved accuracy, ECG heart rhythm monitoring, and barometric altimeter for navigation

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Flextail Zero Power 5k
85 g

Lightweight USB-C power bank with dual ports. At 85g, it's the lightest UL battery pack on the market.

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Coros APEX 4 (42mm) vs Flextail Zero Power 5k: which should you buy?

If saving weight is your priority, the Coros APEX 4 (42mm) wins — at 56 g it is 29 g (34%) lighter than the Flextail Zero Power 5k (85 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.

See where both rank against everything else in this category on the lightest electronics page, or browse the full gear weight database.

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