Cold days bring the best climbing conditions—and the Thorium Jacket lets you make the most of them. Designed for durability, this belay jacket features bold baffling stuffed with 750-fill down for reliable warmth, while the rugged mini-ripstop shell withstands sharp rock. Climbing-specific details like a two-way front zip for harness access and oversized internal dump pockets to keep shoes warm between burns make it an essential layer for the chilliest sessions. What's been updated: The Thorium Jacket is refined for climbers, with increased down fill for added warmth, a boxier fit for better layering, and larger baffles that boost insulation and set it apart visually from past versions.