The heated vest for men guarantees a warm back at the touch of a button. The integrated heating element is not noticeably connected to the Lithium Packs (optionally available for purchase), which sit under the chest ribs. The sleeveless vest has a slim cut to guarantee direct heat transfer. It is worn as the bottom layer. The breathable material is quick drying & abrasion resistant. At higher temperatures, the Heat Vest 1.0 can be worn without the Lithium Packs for sports, work & leisure. It folds up small & has a small pack size. Features Heatable sleeveless vest for men Integrated heating elements in the back area at the level of the kidneys Heated vest fits under any existing clothing system Lithium packs sit in inner vest pockets under chest ribs Can be combined with all Lenz Lithium Packs (optional purchase) Quick drying, wind resistant, breathable & abrasion resistant material Fleece insert in collar Small pack size & folds up small Machine washable at 30 °C