The Massif® Cool Knit® Bottom, made with DuPont™ Nomex® brand fiber, is Massif's lightest flame-resistant performance base layer.The perfect base layer, Massif® Cool Knit® Bottom aggressively wicks sweat away from your skin, keeping you cool and preventing saturation. The lightweight four-way stretch bottom has a trim fit, keeps its shape over time, and is highly compressible for easy stuffing when you're living out of a pack. Constructed with DuPont™ Nomex® brand fiber - the first flame-resistant fiber selected for use in military uniforms. DuPont Nomex fibers carbonize and thicken when exposed to the intense heat of a flash fire, creating a protective barrier that reduces or prevents burn injuries. The Cool Knit Bottom is so soft and comfortable that you'll forget it is FR.Product Features: Full flame-resistant construction with proprietary Massif® fabrics 4-way stretch Excellent moisture management Lightweight Highly compressible Designed to work with the Massif® Fire and Ice™ Layering System All fabrics pass the stringent ASTM D6413-F2302 performance specification for flame resistance Approved by NAVAIR Authorized by the United States Coast Guard USAF Authorized Safe-To-Fly Product Downloads Cool_Knit_2020 Size guide