HydraPak 42mm Filter Cap

Filter water on the go with ease. The instantly transforms your compatible HydraPak bottles and reservoirs into a lightweight, all-in-one water filtration system. Simply thread it onto any 42mm HydraPak Seeker water storage bag or Flux flexible bottle to safely filter fresh water wherever your adventure takes you.

Designed for speed and simplicity, this compact filter allows you to drink directly from your bottle or squeeze clean, potable water into other containers around camp. Whether you’re trail running, hiking, bikepacking, or travelling light, it delivers fast, reliable water treatment without the bulk. Key Features

Light & Compact
Weighing just 57g, this is one of the lightest filtration options available. Its low-profile design takes up virtually no space and can remain threaded onto your bottle when packed.

Dust Cover High-Flow Nozzle
A protective dust cover keeps the drinking nozzle clean, while the high-flow design allows quick, one-handed operation—no need to touch dirty surfaces.

42mm Thread Compatibility
Fits most popular 42mm threaded hydration gear, including HydraPak Seeker water storage bags, Flux bottles, UltraFlask™ and SkyFlask™ handhelds.

Fast, Safe Filtration
Filters up to 1,500 litres of fresh water at a flow rate of approximately 1 litre per minute.

Reliable Protection
Removes 99.99% of E. coli bacteria and parasitic cysts, including Cryptosporidium parvum and Giardia lamblia.

Safe Materials
Made from 100% BPA- and PVC-free materials for peace of mind on every trip. Specifications

Weight: 57 g

Thread Diameter: 42 mm

Filter Capacity: Approx. 1,500 L

Flow Rate: ~1 L per minute

Materials: PP / POM, EPDM, Silicone, Hollow Fibre