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MSR Trail Base Water Filter 4L

To meet the needs of multi-activity backcountry adventurers, we set out to engineer the most versatile water filter ever. The Trail Base microfilter kit features modular components that allow it to be used as a gravity system at camp, a pocket-sized filter on the trail, or a fast-and-light reservoir when you need to carry clean water with you. Whether you’re hiking, biking or basecamping, the Trail Base water filter kit offers incredible flexibility and options, making it the one filter that truly adapts to your adventure and the filtration task at hand.

Effective Against: Bacteria (99.9999%), protozoa (99.9%) and particulate. Hollow fiber filter meets U.S. EPA drinking water standards* and NSF protocol P231 testing standard.

Versatile: Modular components allow system to quickly and easily transform from a 2 or 4 L gravity system into a small trail filter and back.

Simple Transitions: Trail filter simply quick-connects into gravity system to create the complete gravity-fed filter system.

Complete Kit: Includes ultralight, durable clean water reservoir, which features our 3-in-1 cap for easy filling, drinking and pouring.

*U.S. EPA Guide Standard and Protocol for Testing Microbiological Purifiers


Weight:  1 lb 2 oz (0.52kg)

Width: 5 in (12.7cm)

Length:  12 in (10.5cm)

Height:  2.5 in (6.3 cm)

Effective against bacteria:  yes

Effective against chemicals/toxins:  no 

Effective against particulate:  yes 

Effective against protozoa:  yes

Effective against viruses:  no

Filter media:  hollow fibre

Filter pore size (microns):  0.2

Flow (L/min):  1 litre per min

Cartridge life:  1500 litres

Field cleanable:  yes

Field maintainable:  yes

Water bottle adapter: no

Cartridge replacement indicator:  yes

Materials:  hollow fiber

Country of origin:   Made in the USA of US and Imported Materials