Why use something that requires any kind of power source, when you have the greatest force on earth to do the job? The force I'm referring to is called gravity. Once you have inserted most of the meter of hose in the donor tank and plugged the free end with a finger (I use my thumb), you just lower the free end below the surface of the liquid in the tank and gravity takes car of the rest. I avoid carrying any extra equipment that needs a power source that can brake, when I travel. You will however need a bottle, but those people throw away almost everywhere, except here in Finland. But to everyone according to his/hers/it's/undefined genders needs.