The Mobile Warming® Bluetooth®-enabled Primer heated baselayer shirt is designed for the outdoor enthusiast. From skiing, hunting, hiking to running or just working outdoors, the Primer Shirt complements your outerwear to keep a warm core. Its moisture-wicking, warmth, and stretch features make it a versatile baselayer in the winter, or a standalone shirt during outdoor activities in the Spring and Fall. The Primer is made from a four-way stretch anti-microbial polyester-spandex blend that provides a comfortable next-to-skin feel. Flat-lock seams, moisture-wicking mesh liner, and side-stretch panels conform to your body and allow for maximum body movement. The Primer heated baselayer has integrated, concealed heating panels powered by sturdy yet light-weight 7.4-volt Far-Infrared Heating System. The 7.4-volt system has three heating elements, one on the back and two on the chest, that add heat to critical areas that keep your core warm. The Primer’s 7.4-volt heating system can provide temperatures ranging from 135°F on high to 90°F on low. On high, expect 2.5 hours of heat, and on low, the Primer can provide heat for up to 10 hours! The Primer has two ways to adjust the temperature. First, the built-in touch control button. With a simple button push, you can select from four heat settings. Second, we’ve incorporated Bluetooth® control with our MW Connect™ app. Through the MW Connect™ app, you can quickly toggle through all connected Mobile Warming® devices and adjust individual heat levels to your liking. MW Connect™ allows you to get real-time updates on battery levels and update your garments when new firmware becomes available. All day, any weather. The Primer heated baselayer shirt is a versatile insulating layer that keeps you warm all winter long.