Combining 100g of premium PrimaLoft warmth-holding insulation and a front and back battery-powered heating element, the H.E.A.T. liner vest has got you covered. The Tri-Zone heating is selectable for three levels of customizable heating, so dial-up what you need when you need. Use the integrated iPhone charging cable to keep your phone ready for those post-hunt pics. Elastic cuffs and adjustable drawstring waist keep the warmth in.