Mens Tourmaster Synergy 2.0 Vest Liner With Collar - X-Large Designed to operate in all weather conditions from a vehicle&rsquo;s 12-volt electrical system Warmth without bulk or discomfort, making for a safer, more enjoyable ride Lightweight, flexible steel fiber heating elements provide safe, even warmth Expanding side panels help fine tune the fit and increase comfort Water-resistant, dual rheostat included (single rheostat available)