DetailsSantiam Alpine Shell Size Chart The CIRQ Santiam 3 Layer Jacket is a packable alpine shell designed for fast paced activities in the heavy snow or pouring rain. Made with a 3 layer polyester construction that achieves both weather protection and breathability along with a soft next to skin feel. The polyester shell repels water thanks to a Teflon Shield+ finish, and the hood adjusts with front and back drawcords. This jacket is cut to allow room to be worn with your favorite insulated layer. The Santiam Alpine Shell is a relaxed fit, made to accommodate your favorite fleece or insulated mid-layers.