I would worry about a water supply first for survival, I like the attached one it has a gauge and is good for 13,000 gals. The rebuild , cleaning kit is well worth it money and time. Not having to carry water every where you go , water is 8ibs per gal it would be easier to fill small...

i bought one of those sprots bottles that has the filter in it thought it might be something good to have to keep in the car am going to try it out this weekend and will give a report what i thought of it