12V heated jacket liner is the perfect addition for riders wanting complete comfort, regardless of the temperature. Durable, wind-resistant nylon chassis, this liner comes with 7 Microwire™-powered heat zones in the collar (1), chest (2), sleeves (2), and back (2). Designed to be worn as a mid-layer, under a protective jacket. Microwire™ heat zones come to full temperature in seconds. Liner also serves as "home base" for Gerbing heated gloves, pants and sock connections. Pre-wired glove connections at end of sleeves. Low-profile elastic cuff for improved fit under jacket. Mini-ripstop Nylon shell with Taffeta lining. ThermoGauge Bluetooth Compatible. Drop tail back for improved coverage while riding. YKK Zipper. Sizing XS through 4XL, and three long sizes: M/Long, L/Long and XL/Long. All Gerbing installations require a Battery Harness and Temperature Controller for operation (sold separately).. We recommend the use of a temperature controller with this product. Failure to do so may cause discomfort & burns..