Description of Sierra Designs Drizone™ Primaloft® Packable Booties Grab a cup of hot cocoa and sit by the fire with your toes nicely warmed in the comforts of Sierra Designs Primaloft Booties. Features: Drizone™Waterproof/Breathable: 100% Nylon Ripstop with Primaloft® Sport Synthetic Insulation Super lightweight and packable Reinforced ankle to keep foot from slipping Elastic cuff Comes with a stuff sack