The Helly Hansen Lifaloft Insulator jacket uses the highly compressible and very warm LifaLoft Insulation. The ingenuity in this puffy does not stop there, the outer layer is windproof and water resistant while being insanely packable thanks to the insulation. The tapered sides allow for both a great fit and easy mobility. The jacket can do it all, from being an outer layer on cooler days to a layering piece on the coldest of days.