At ElectronicFaucet.com, one can find a wide range of bathroom accessories, including toilet paper dispensers, hands-free towel roll dispensers, and electronic hand dryers, and grab bars in 22+ different finishes!
Automatic paper towel dispensers have a motion sensing system that detects when someone waves their hand in front of it and then proceeds to release a set amount of paper towels onto said person's hands. It provides better control over how much paper one uses on use.
That depends on the model you have opted for your use from ElectronicFaucet.com. The majority of the paper towel dispensers uses 4x Duracell D size batteries