Lightweight Reactor is intelligent insulation that adapts to your activity level for the right breathability & warmth for what you're doing. Center-front waistband UA Speedpocket expands to keep your goods totally secure; it's water-resistant & bounce-free. 4-way stretch construction moves better in every direction. Anti-odor technology is a superlative innovation which helps prevents odor. Soft, knit waistband with interior drawcord ensures a secure, comfortable fit