Ok, follow up question. I just picked one of these bad boys up and there is an instruction sheet that has more silly pictures than words (read: useable information) and it states that if you can blow air through the filter, that its cracked. But based on the tiny bubble diagram, I imagine they mean to say that small air bubbles appearing before you blow ALL the water back through the filter means that its cracked. Input?

Tech Specs:

Filter Material:

Hollow Fiber 

Output:

1.75 L 1 min 

Removes:

protazoa, bacteria, particles 

Field-Cleanable:

yes 

Dimensions:

4 in 6 in 

Gravity Flow:

yes 

Cartridge Life:

1500 L 

Weight:

13.8 oz 

Recommended Use:

backpacking, expeditions, basecamp 

Manufacturer Warranty:

1 year