The PCU Level 1B Thermal Bottom is the foundation layer of the ECWCS system, designed to be worn next to your skin for superior comfort and performance. Highly moisture-wicking, breathable jersey fabric draws perspiration away from your skin to keep you dry and comfortable, while the lightweight construction and form-fitting design provide excellent range of motion without adding bulk. Ideal for three-season use and compatible with the advanced SOF-PCU clothing system. PCU Level 1B Thermal Bottom (Protective Combat Uniform) ECWCS Level 1 base layer Moisture-wicking and breathable jersey fabric Lightweight construction for maximum comfort and mobility Form-fitting design with excellent range of motion SOF-PCU compatible