Filson M's Denim Jac-Shirt

Long trusted for work in the West, denim brings weight and structure to this insulated layer. The heavy-duty 15-oz. shell blocks cold wind. The body is lined with high-pile fleece for warmth, while the sleeves are insulated with quilted polyester to reduce bulk and layer cleanly.

Cut like a shirt, it's a straightforward layer that stays warm without feeling oversized. Side-seam slits at the hem improve mobility when bending, reaching, or sitting. Button-flap chest pockets keep essentials secure and close at hand.