Building on the ever popular Aggressor 2.0 Shirt this heated base layer was made to maintain ultimate comfort levels from a light chill in the air to the coldest days attacking the mountain. Gridded fabric design traps heat Flat low-profile seams for excellent minimum-bulk layering Engineered specifically for power sports Poly-spandex blend Anti-microbial Moisture-wicking Highly breathable Fast-drying Lighter thinner gussets in underarms reduce bulk and increase breathability/mobility Designed specifically for use with KLIM mid-layers and outerwear Convertible cuff construction easily used as thumbhole or regular cuff HEAT SYSTEM Heat panels on chest & back (2 upper chest (1 on each side) and 1 vertical on the mid-upper back) Lighted touch button control on upper right chest (out of the way of backpacks straps, easy to access) Internal wire routing for comfort 3 Heat modes: high/medium/low (and off) Up to 8 hours on low heat (green light) ?Up to 3.5 hours on medium heat (blue light)? Up to 2.5 hours on high heat (red light)? Red-blue-green heat level lighting code USB-C battery with LED battery life indicator USB-C cable included Washer & dryer safe (with battery removed) Dedicated battery pocket? Replacement batteries available