AT Hybrid AT Hybrid’s insulated, windproof body panels and side panels with 4-stretch are a winning combination. The 37.5 insulation keeps you comfortable by helping to control your core temperature while the stretch panels enhance fit and freedom of movement. The AT Hybrid Vest is an ultra-lightweight technical piece that is flattering and comfortable. FEATURES Stretch side panels for fit and freedom of movement 37.5 technology is chemical free, permanent, and never washes out or gets tired. Chemical-free, natural insulation Stand-up, zip-through collar with chin-guard Zippered hand warmer pockets. Keep your game sharp with this reliable, comfortable, and stylish gear — made for modern golfers who want performance with personality.