100% Nylon, 20K/15K waterproof breathable Fabric Bio-Heatsol Insulation Body heat reflective lining Meet a history-making jacket: The Tempest Duty. 5.11's introductory Next Level Uniform jacket is also the most waterproof and breathable we've ever made. The waterproof shell is to increase wearer safety, while the traditional Ike Length design provides easy access to your duty belt.. For incredibly lightweight warmth, we combined patented Bio-Heatsol technology (which emits heat and infrared waves through your body) with a silver patterned lining (which reflects body heat from the jacket back to you). This jacket is fully seam-sealed to keep you dry in wet weather, and features pullout ID panels at the chest and back.