"It's for any outdoors enthusiast who is deep in the woods and doesn't have access to a power outlet or for a commuter who constantly needs backup battery power," said Jessica Davis of Tremont. "You could use this for an emergency situation or just for your commute."

In addition to hikers, any person whose daily routine includes a lot of walking or other vigorous activity would be part of the target market for the PEG, including college students, members of the armed forces, emergency first responders, and foot and bike commuters.

PEG batons are nine inches (23 centimeters) long and weigh 11 ounces (312 grams). Floating magnets sliding through coils generate the electricity. The batons fit in a backpack, briefcase, or runner's pouch. They sync to up-and-down motion to generate power. If more power is required, the user can grab the rod and shake it vigorously.

"It tunes to optimize the amount of power being produced," Davis said.

The PEG device works with more than 3,000 handheld devices that are USB 2.0 compatible.

Tremont, an Ohio-based company, began selling the $160 "kinetic" chargers in September 2010, and it has had a difficult time keeping up with the high demand.