Compact and superlight, our lightest Atom vest easily stashes in your pack, ready to grab when summer temperatures drop. Worn as a midlayer or standalone, it delivers moderate insulation perfect for early morning runs and taking in the view from a freshly bagged peak. The Tyono 20 shell balances breathability and wind resistance, and the Coreloft insulation is light, compressible, and efficient. Lightweight stretch fleece side panels improve ventilation and hold the fit.