Designed for intense activity in cold weather, the PROTON VEST from Arc'Teryx is an insulating, lightweight and breathable sleeveless jacket for men.

Whether worn for hiking, trail running or climbing, this model provides the thermal regulation needed for sporting endeavors, offering theperfect balance between ventilation and insulation, enveloping the torso to protect it from the cold while preventing overheating. Durable and stretchable, the Fortius Air 20 softshell outer material provides moderate protection against wind and weather, while promoting ventilation. What's more,Octa Loft insulation keeps you warm and preserves its loft season after season.

This jacket adds a chest pocket for a radio, and is cut to fit easily under a shell jacket.