When you’re in motion – climbing, hiking, running trails – regulating thermal comfort is essential. Made to balance air flow and insulation, the Proton Vest wraps the core to deliver warmth without overheating. Softshell durable, the Fortius™ Air 20 outer stretches, and balances moderate wind and weather protection with airflow. Octa® Loft knit insulation provides warmth that resists packing out over time. The chest pocket is sized for a radio, and the trim fit layers easily under a shell.

Updated with a revised fit.