I have several BOBs. All for different things. My big BOB is a light weight back pack from Outdoor products. It weighs 22 lbs with enough to survive for the longest term. I've used it for up to 6 weeks in the woods. Next is my regular BOB, it is smaller and weighs about 13 lbs loaded and I can do fine for about a week or a little longer. Then there's my baby BOB that I usually have near me at all times. It weighs about 8 lbs loaded and can sustain me for about 3 days or a little longer. What I look for in a back pack is, it has to be lightweight, have a lot of pockets and it has to be comfortable.