Trail Base Water Filter Kit - 4L (Fall 2022)



Ultra-versatile system with gravity filter for camp and a small filter for the trail

The most versatile water filter MSR has ever designed, the Trail Base 4L microfilter kit features the same smart engineering and modular design of the 2L version with twice the water capacity for just an extra 2 oz in weight. The kit lets you use the gravity system at basecamp, the pocket-sized, take-alone trail filter for on-the-fly hydration, and the fast-and-light reservoir for hiking or biking, or whenever you want to carry more clean water with you. The kit directly connects to standard hydration system reservoirs for hassle-free filling. And with the shake-to-clean filter, it’s super easy to clean—no backflushing required.

International Restrictions Apply

California WARNING: Cancer and Reproductive Harm –


Brand Name:
Micron Rating:
Flow Rate:
1 liter per min
Treatment Type:
Gravity Filter
18.2 oz / 516 g
Protects Against:
Protozoa and Bacteria
Filter Material:
Hollow Fibers
Field Maintainable:
Mfg Sku/Part Number:
Other Features:
• 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 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 a 3-in-1 cap for easy filling, drinking and pouring.
• Flow (strokes per liter): 60
• Cartridge life: 1500 liters
• Cartridge replacement indicator: yes
• Made in the USA of US and Imported Materials
*U.S. EPA Guide Standard and Protocol for Testing Microbiological Purifiers

Recommended Accessories