Mythic Ultra

The Mythic Ultra is built for alpinists and winter backpackers who prioritize absolute warmth per gram over rugged utility. By pairing premium 900-fill-power hydrophobic goose down with a heat-reflective TILT lining, Rab produced an exceptionally warm insulating piece that compresses down to the size of a standard water bottle. It caters squarely to fast-and-light mountain objectives where sub-zero bivies or freezing belay stances are non-negotiable, but pack weight must stay strictly managed.

Underneath the gossamer 10D Pertex Quantum shell, the construction shifts strategically between box-wall baffles around the core to prevent cold spots and lighter stitch-through baffles on the sleeves to preserve arm mobility. The internal TILT scrim bounces radiant body heat back toward your torso without choking breathability or adding perceptible bulk. In the field, the thermal output feels comparable to heavyweight expedition parkas that weigh nearly double, though the featherweight face fabric demands constant awareness around jagged rock, crampons, and ice tools.

As an ultralight specialist piece, durability is the obvious concession. The 10-denier outer will not tolerate abrasive granite chimneys, bushwhacking, or careless packing alongside sharp hardware. It also commands a steep price tag compared to standard 800-fill workhorses like Rab's own Neutrino Pro. Yet for high-altitude pushes or minimalist winter traverses where every single ounce directly impacts success, the warmth-to-weight ratio remains practically peerless.