"This power pack charges 3 USB devices at once, plus I use it for powering 12V DC electronics like my portable air pump. Its really convenient adding air to my tires without messy power cords. I simply plug the air pump power cord into the DC port on the power pack and fill them up. When away from traditional power outlets, connecting a 12V DC-powered air pump also works great for filling inflatable paddle boards & air mattresses at the lake. No tangles, no mess very nice!"