Fox 40 Micro Whistle vs Sawyer Squeeze SP131

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

Fox 40 Micro Whistle is the lighter option — 75 g lighter than the Sawyer Squeeze SP131 (88% less weight). If grams matter to you, that is the one to beat.

Spec	Fox 40 Micro Whistle	Sawyer Squeeze SP131
Weight	10 g · 0.010 kg · 0.02 lb	85 g · 0.085 kg · 0.19 lb
Brand	Fox 40	Sawyer
Category	Safety	Safety

Fox 40 Micro Whistle

10 g

Pealess safety whistle audible up to 1km.

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Sawyer Squeeze SP131

85 g

0.1-micron squeeze water filter removing 99.99999% of bacteria and 99.9999% of protozoa. Includes three BPA-free pouches.

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Fox 40 Micro Whistle vs Sawyer Squeeze SP131: which should you buy?

If saving weight is your priority, the Fox 40 Micro Whistle wins — at 10 g it is 75 g (88%) lighter than the Sawyer Squeeze SP131 (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 safety page, or browse the full gear weight database.

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