One avalanche rescue backpack per person containing a cartridge of compressed gas in Division 2.2 Without a subsidiary risk. The avalanche rescue backpack may also be equipped with a pyrotechnic trigger mechanism containing not more than 200 mg net of explosive in Division 1.4s. The backpack must be packed in such a manner that it cannot be accidentally adtivated. The air bags within the backpacks must be fitted with pressure relief valves.