Katadyn BeFree AC Water Filter vs SOL Thermal Bivvy

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

Katadyn BeFree AC Water Filter is the lighter option — 105 g lighter than the SOL Thermal Bivvy (62% less weight). If grams matter to you, that is the one to beat.

Spec	Katadyn BeFree AC Water Filter	SOL Thermal Bivvy
Weight	65 g · 0.065 kg · 0.14 lb	170 g · 0.170 kg · 0.37 lb
Brand	Katadyn	SOL
Category	Safety	Safety

Katadyn BeFree AC Water Filter

65 g

0.1-micron hollow fiber filter integrated into a collapsible soft flask. 1,000L lifespan, fast flow rate. New AC version adds activated carbon filtration for im...

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SOL Thermal Bivvy

170 g

Reusable emergency bivvy. Warmer than mylar alternatives.

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Katadyn BeFree AC Water Filter vs SOL Thermal Bivvy: which should you buy?

If saving weight is your priority, the Katadyn BeFree AC Water Filter wins — at 65 g it is 105 g (62%) lighter than the SOL Thermal Bivvy (170 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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