The Ranpart Jacket from M.E. is a single layer that can be thrown on to provide you with a highly windproof barrier as well as lightweight synthetic insulation. This is thanks to the Helium 50 outer fabric that stops the wind from pushing out warm air trapped within the Polarloft Micro insulation. It is amazingly packable as it all fits into it own pocket for storage with a handy krab loop, so when not in use you can clip it to your harness in between belay points; you can even use it as a super warm mid layer. Polarloft Micro itself is made up from a mix of 3D long filament fibres and micro fibres. These fibres work together regulating temperature as you move. It provides impressive moisture management which aids the removal of excess heat & moisture when you are active. As this jacket is hoodless, M.E. have fitted the neck with an adjustable drawcord, so you can keep out snowfall & the cold winter winds. Helium 50 outer is exceptionally lightweight & windproof 80g POLARLOFT Micro quilted insulation YKK centre front zip 2 zipped hand warmer pockets Inner zipped security pocket Adjustable neck drawcord Lycra bound cuffs & hem drawcord Packs into hand pocket with karabiner carry loop 100% Polyamide outer/ Polyester inner, 100% Polyester fill 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. Polar Loft Micro Windstopper Soft Shell Dual Tether Hem Drawcord Mountain Fit Most people are scared to wash & reproof their outdoor 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 kit. Nikwax Tech Wash Nikwax TX-Direct I hope this helps.