Sorry... I just meant the fabric is kinda stiff. It still folds flat. But really... the idea is that you keep the battery in it all the time unless it's being run. It makes a really nice little storage system.
Btw, I also have a cool "hardcase" one too. It's a plastic case like an old-school nimh carry case. I'm not happy with it quite yet but it's getting there. The material for that one is rated @ 3000*F and it will hold like 4 packs and have some isolation between them
That would be a much better deal than the $20-30 bags on the market now.