i wasnt sure where to put this, its not really a recorder or a player, but a video transferer.Anyone got one of these?

I planning to get one, but i realized that it dont run on batteries, and i need it
to be portable.Does anyone know what i need to hook this up to an external battery? Is it possible? If so, what kind of battery do i need?

I've seen some 'universal' external battery packs, but i think they are very costly for me.