Grayl UltraPress Purifier vs HydraPak 42mm Filter Cap

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

HydraPak 42mm Filter Cap is the lighter option — 252 g lighter than the Grayl UltraPress Purifier (82% less weight). If grams matter to you, that is the one to beat.

Spec	Grayl UltraPress Purifier	HydraPak 42mm Filter Cap
Weight	309 g · 0.309 kg · 0.68 lb	57 g · 0.057 kg · 0.13 lb
Brand	Grayl	HydraPak
Category	Hygiene	Hygiene

Grayl UltraPress Purifier

309 g

Press-style 16.9oz bottle purifier using electroadsorption and activated carbon; removes viruses, bacteria and protozoa.

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HydraPak 42mm Filter Cap

57 g

Lightweight fast-flow filter cap that threads onto 42mm bottles, removing bacteria and cysts for hiking and travel.

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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 252 g (82%) lighter than the Grayl UltraPress Purifier (309 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.

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