Nike Thermo Handwarmer Nike Therma-FIT Technology uses insulating fabric to keep your hands warm in the Thermo Handwarmer. Its weather-resistant shell protects against the elements while a secure internal pocket provides convenient storage for your mouthguard or a heat pack. Built with an adjustable quick-release belt that will attach securely around waists up to 44". Rubberized Swoosh design trademark. 30% nylon/25% cotton/22% polyester/15% polypropylene/8% polyurethane. Imported. Sz: Fits waist up to 44".