Bear Grylls Emergency Bivy vs Katadyn BeFree AC Water Filter
Weight and specs compared for 2026 — and which one to choose.
Tear and puncture-resistant mylar bivy. Only 4 oz for emergency backup shelter.
Full details →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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Bear Grylls Emergency Bivy vs Katadyn BeFree AC Water Filter: which should you buy?
If saving weight is your priority, the Katadyn BeFree AC Water Filter wins — at 65 g it is 48 g (42%) lighter than the Bear Grylls Emergency Bivy (113 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.