Ultralight 30°F/-1°C Thermally efficient and comfortable, Flex™ is designed into the mid portion of the bag, where you move most.
ThermoDry™ TECH offers superior synthetic insulation, which is durable, lightweight and weather resistant. The Jacket Hood guarantees warmth down to 30 degrees and foot box vent allows for cooling on warmer nights.
For superior comfort and heat retention, Sierra Designs incorporates Flex technology into several insulated jackets and sleeping bags. With elastic built into the baffles of both down and synthetic jackets and bags, Flex technology hugs the body, eliminates dead air space, and keeps warm air close to the body. And beyond just keeping you warmer, Flex jackets and sleeping bags move with you for better mobility and a more comfortable night’s sleep.