Grayl UltraPress Purifier vs HydraPak 42mm Filter Cap
Weight and specs compared for 2026 — and which one to choose.
Press-style 16.9oz bottle purifier using electroadsorption and activated carbon; removes viruses, bacteria and protozoa.
Lightweight fast-flow filter cap that threads onto 42mm bottles, removing bacteria and cysts for hiking and travel.
Building a pack? Add either one to your HikeLoad list, or drop its weight into the base weight calculator, and see what it does to your total weight.
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Grayl UltraPress Purifier vs HydraPak 42mm Filter Cap: which should you buy?
If saving weight is your priority, the HydraPak 42mm Filter Cap wins — at 57 g it is 297 g (84%) lighter than the Grayl UltraPress Purifier (354 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 hygiene page, or browse the full gear weight database.