Mountain Equipment made the Helium 600 14 Down Sleeping Bag superlight and highly compressible for backpackers. The Helium truly lives up to its name, with lightweight 725 fill down insulation and an ultralight Helium shell that compresses for compact storage. A slanted baffle construction assists with compression and keeps the down in place to prevent cold spots. An alpine mummy fit offers a little more room for extra comfort. Inside the Helium, you get a Supersoft 20 lining to keep you cozy throughout the night. Like the bag, the DC5 hood's baffled construction keeps the down in place for a cushy head space. Mountain Equipment also added a roomy Trapezium 4 footbox, a draft blocking Solus collar, and draft tubes down the side zipper.