As part of the Performance Series, these Mobile Warming Merino Heated Baselayer Pants are powered by a rechargeable Lithium-Ion battery, which delivers up to 10 hours of effective heating comfort supported by a universal USB charging port. Designed for versatility, wear this as a base layer to deliver unparalleled levels of warmth and safety. It's naturally breathable merino-knit is ideal for fall or spring hunts, hikes or any of your favorite outdoor activities. As the temperatures dip, simply activate one of four heat settings with the Bluetooth integrated MW Connect app. Multi-zone heating elements keep your legs warm and internal temperature regulated in even the harshest winter conditions. These are designed with a sleek profile that comfortably fits under your favorite hunting pants, bibs, jeans, or even ski and snowboarding pants.FeaturesHeavyweight Base LayerMulti-Zone Heat Elements: 2x Inner Thigh & 1x Upper WaistBluetooth Control with MW Connect available on the App Store ...