The Patrol E2 30 Kit backpack carries Scott's Alpride E2 system, an electronic avalanche airbag built around a supercapacitor instead of a canister or lithium battery. That supercapacitor holds its charge and performance in cold temperatures, and the mechanical trigger and deflation release remove any dependence on an electronic signal to work. Two AA batteries power the whole system, so a recharge on the mountain never depends on finding a refill station or replacement cartridge. At 2830 grams with the airbag system installed, the pack carries that safety mechanism inside a 30-liter CORDURA build sized for a full day of backcountry travel. What Our Gearhead(R) Experts Are Saying:"I've flown with this pack without a second thought about cartridges or lithium batteries getting flagged at security. Two spare AA batteries in my jacket pocket and I'm covered for the whole trip, no refill station required."