Rab Carrington (as in the Rab in Rab!) originally devised the Vapour-Rise concept by combining the technology of high wicking micro fleece & Pertex Equilibrium fabrics to produce a single garment with a 2 layer construction that offers superb weather protection & immense breathability. The brand new Vapour-Rise Flex Pullon combines the performance of VR fabrics with the comfort & stretch of Matrix SWS side panels to produce a supremely lightweight, highly breathable & incredibly comfortable pullon resulting in a feather weight, high wicking top that works as a base layer, mid layer or outer layer. This incredibly versatile top offers year round protection for mountain activities by balancing comfort, windproofing & breathability; what more could you need? The 2 layer Vapour-Rise technology uses your body heat acts as a pump working with the micro fleece brushed lining to push moisture away from your skin & move it to the face fabric. Pertex Equilibrium face fabric has larger filaments on the inside & smaller filaments on the outside. The laws of capillary action dictate that moisture will move from large filaments to smaller ones, pulling your sweat away from the lining & spreading it out over the large outer surface area. This evaporative heat loss & moisture wicking create a temperature equilibrium to keep you comfortable & dry in all conditions. Finally a robust DWR treatment on the outside repels water. Rabs own Matrix SWS stretch softshell panels under the arms & down the sides ensure a close fit to maximise the wicking performance of the lining & provide unrestricted movement. Because the Vapour-Rise Flex Pullon breathes so well it works perfectly as mid layer under your hardshell if the weather turns really nasty. We recommend using the Rab Aeon Tee under Vapour Rise garments as its silky smooth fabric glides smoothly against the VRs wicking liner & maximises the wicking properties. Pertex Equilibrium outer fabric Wicking micro fleece drop liner Matrix SWS stretch softshell side & underarm panels 2 way YKK deep venting chest zip with internal storm flap & chin guard Fitted collar YKK zipped chest pocket YKK zipped internal pocket that doubles as stuff sack Semi elasticated cuffs Half hem drawcord Slim fit