Mountain Equipment have two down jackets which utilise lightweight but highly protective Gore Infinium. This version, the Xeros is the lightest with 140g of down and a simpler, more packable feature set for technical adventures.
Mountain Equipment says:
A super-lightweight and highly protective down jacket for the hardest modern Alpine routes.
Part of an extended R&D project with some of the best Alpinists in the world, this minimalist down jacket has been developed to offer maximum protection and warmth for the least possible weight and pack size. With a GORE-TEX INFINIUM™ drop outer shell, insulation and weather resistance are optimised.
Mountain Equipment's Xeros Down Jacket uses 140g of 800 fill down which provides a good amount of warmth especially when that heat is sealed in with the Gore-Tex Infinuim outer fabric. This is still a great jacket for cold weather but it is more versatile thanks to the lower fill of down and the minimalist features set. The combination of fabrics and fill give you all the warmth you need for normal trips in colder conditions but the ability to pack and carry this jacket make it more usable year-round.
This jacket uses lightweight 10D Gore Infinium fabric to provide windproof and highly water-resistant protection that is ideally suited to harsh conditions where this level of protection is vital. A Super Alpine hood provides excellent coverage while the limited feature set elsewhere on the jacket show a focus on reducing the weight and bulk adding to its versatility. The stitch-through construction of the baffles also helps keep the weight and bulk.