For years my spent camera batteries have always ended up in the bottom of my pack. They were only to be found during full pack dumps, which rarely happens unless I'm taking a big trip. I would always write them off as being lost and pick up new ones. Not anymore! This little sack is genius and perfect! I always keep my fully charged batteries in a little bag so this solution combines my charged with the spent. It's so well made and I really enjoy it. I just ordered a 2nd one for my dad. He tends to throw spent batteries in the black hole of his camera bag.