What Our Gearhead(R) Experts Are Saying:"I took this on a late-season alpine trip where temps dropped into the teens overnight, and it held heat really well without feeling bulky. It packs down small, and I appreciated how evenly the insulation stayed in place through a few nights of use."Cold alpine nights demand a system we can trust, and the Neutrino 10F Sleeping Bag from Rab is built for exactly that. Whether we're pushing into higher elevations or settling into a cold-weather camp after a long day on the move, this bag keeps us warm without weighing down the pack. Packed with 800-fill goose down and built with L. O. F. T 3D(TM) baffle construction, it maximizes heat retention while eliminating cold spots across the bag. A tapered mummy shape seals in warmth, while the Pertex(R) Quantum fabrics balance durability and packability by reinforcing high-wear zones like the base and footbox. Thoughtful details like a down-filled collar, adjustable hood, and insulated zip baffle help trap heat where it matters most, while the two-way zip allows us to vent when temperatures shift overnight.