"The La Sportiva Lumina 300 Down Jacket packs 1000 fill power Italian down into strategically designed chambers, so real warmth shows up at a cold belay stop or a pre-dawn start instead of getting lost chasing a lighter number on a spec sheet. Elasticated inner cuffs seal that warmth in at rest, while a Pertex® Quantum shell with Diamond Fuse technology stands up to the abrasion of rock, gear, and a loaded pack. When it's time to move, the jacket compresses into its own stuff sack, taking up almost nothing until the next stop. What Our Gearhead® Experts Are Saying:""I stood at a cold belay before sunrise and stayed warm long enough to actually enjoy the view, then stuffed the jacket down to nothing for the climb itself. That kind of warmth-to-weight ratio is the difference between tolerating a belay and being comfortable through it."""