Black Diamond Agent avalung 

Volume : [S/M] 18L ( 1,098 cu in); [M/L] 20 L (1,222 cu in)
Average Stock Weight : 1.49 kg (3 lb 4 oz) estimated
Materials : 800d Ballistic, 420d Velocity nylon

The Black Diamond Agent AvaLung is streamlined enough to ride the lift up for sidecountry laps, yet has enough room for avy-tool essentials on longer day missions in the backcountry. In the event of an avalanche burial, the built-in AvaLung increases your chance of survival by pulling fresh air from the surrounding snowpack. Our diagonal ski carry cable is ultra-secure for hikes, and the innovative HiLo helmet holder gets your lid off when you're really sweating for those turns.