Fieldsheer Men's Merino Heated Long Sleeve Base Layer Shirt - Designed for versatility, wear this as a base layer to deliver unparalleled levels of warmth and core comfort. It also doubles as a shirt, and its naturally breathable merino-knit is ideal for fall or spring hikes or any favorite outdoor activity. Heavyweight base layer Contour fit hoodie for extra warmth In-seam thumb holes on cuffs Waist and chest pockets Multi-Zone heat elements: 2x Chest and 1x Back MW Connect Mobile App Compatible available on App Store and Google Play Integrated touch control button 4 selectable heat settings 7.4volt rechargeable Lithium-Ion battery Up to 10 hours of power per charge Universal USB charging input Style: MWMT14010321