There are two powerful models of pepper spray. Both are effective and does a great job at fending off a bear in case of an attack.
Bear repellent spray uses a special FDA approved formual and ordinary pepper spray is not recommended to use against bears.
The Sierra Club wants the Forest Service to require everyone who enters a national forest in grizzly bear country to carry bear spray Spokeswoman Heidi Godwin said in a news release, "The proper use of bear repellent pepper spray will reduce human injuries caused by bears, reduce the number of grizzly bears killed in self defense, and help promote the recovery and survival of the grizzly bear."