Clocking in at only 245-grams, the men's Proton LT Vest is an exceptionally light, airy, and warm Arc'teryx softshell. Its intended for use as a cool weather standalone or as a mid layer under a hardshell during alpine activities. It derives its warmth from a padding of ultra-light Coreloft™ Continuous 65 insulation. A Fortius™ Air 40 outer fabric balances wind and water resistance with air permeability, for all day comfort across a range of conditions. Arc'teryx equipped the Proton LT vest with two insulated hand warming pockets and gave it a convenient zippered chest pocket. It's collar height provides ample coverage and warmth. A No Slip Zip™ front zipper prevents self-opening during physical activities. The hem has dual adjusters that tighten to block out cold drafts.