Duracell Plus Battery - 2 x D batteries per card. When it comes to easily-forgotten camping accessories, batteries have to be right up there along with mugs, adaptors, and whatever lead is the most indispensible!
It isn't just certain pieces of camping equipment that run off batteries, such as some lanterns, but your personal bits too, like music players and cameras, so don't go without because when you're tucked up in your camping tent and your torch dies you'll be sorry!