Simply fill up the pouch at a lake, stream, or river, screw the filter directly onto the pouch, and then squeeze the bag to filter water into a bottle. ... Rated to 0.1 micron absolute filtration, it removes 99.99999% of all bacteria, such as salmonella, leptospirosis, cholera and E. Kit Includes SP129: Squeeze Filter with Push/Pull Cap 2 - 32 ounce Collapsible Pouches Backwashing Plunger Inline Adapters Drinking Straw or Gravity Tube Mesh Carrying Pouch (can also be used to create gravity water filtration system) SP131: Squeeze Filter with Push/Pull Cap 16 ounce Collapsible Pouch 2 - 64 ounce Collapsible Pouch Backwashing Plunger Cleaning Coupling Inline Adapters Drinking Straw or Gravity Tube Mesh Carrying Pouch (can also be used to create gravity water filtration system) Technical Specs Best Use- Backpacking Filter Type- Squeeze Gravity Filter Medium- Hollow-fiber membrane Removes/Destroys- Protozoa and Bacteria Pump Force- Not applicable Pump Strokes Per Liter- Not applicable Output- 1.7 liters per min. Housing Material- ABS plastic Field Cleanable- Yes Dimensions- Filter: 5 x 2; squeeze pouch: 11 x 6 inches Weight- 3 ounces