Breathable
This means that the item has been treated with a micro porous membrane that passes humidity from the inside to the layer on top while keeping fluids from the upper layer out. This technology makes sure that transpiration fluids and condensation are easily disposed of while rain and other fluids are kept out. This keeps you dry, but also insulated against the harshest of weather conditions. The "mpv" indication shows you the item’s breathability, which is determined by the amount of condensation that the fabric will let pass.