This ultimate alpine jacket is the king of lightweight insulation. The micro baffle construction holds the WR Down 675 from migrating, & the light weight Helium 30 fabric is super light & allows the down to fully loft; this ensures the maximum amount of tiny air pockets are created to capture your body heat while the wind resistant qualities help prevent the loss of this heat. The use of down ensures the best warmth to weight ratio & compressibility compared to any other forms of insulation. With a slightly longer cut, an adjustable Mountain HC hood & the fact it packs into its own pocket with a handy crab loop; you can stow & clip you jacket onto your harness so it‘s easy to get at & throw on when waiting around & belaying. The Lycra cuffs reduces bulk when layering & the adjustable dual tether hem draw cords provide that extra bit of security. M.E. only uses Down Codex Audited Animal Welfare approved sources for all their Down filled products marked with the Down Codex Stamp. 2014 autumn/winter updates 134g (Size L) of water resistant 90/10 Pure Down with a fill power of 675 Carry over features Helium 30 outer shell is exceptionally lightweight and downproof Stitched-through narrow baffle construction throughout Adjustable Mountain HC Hood 2-way YKK moulded centre front zip 2 zipped hand warmer pockets Napoleon chest pocket Lycra bound cuffs & adjustable dual tether hem drawcords Packs into hand pocket with karabiner carry loop For all you kit geeks out there, the links below will take you to Mountain Equipments Information pages where they will explain this jackets different fabrics, fills & constructions techniques in greater detail. Helium 30 WR 675 Down (WR means the down has been treated with a water repellent coating to improve moisture management, currently wait for M.E. to update this section) Dual Tether Hem Drawcords Most people are scared to wash their down jackets but like all equipment it does need to be maintained. It is actually really easy! Feel free to give the shop a call from 09:00 until 17:30 Monday to Saturday (19:30 on a Wednesday), as we are always happy to help & give friendly advice. Or if you are reading this outside our normal opening hours here is a useful link to Trekitts recommended product for washing & caring for down Nikwax Down Wash I hope this helps.