Tourmaster Synergy 2.0 Black Vest w/Collar Liner size X-Small Designed to operate in all weather conditions from a vehicles 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, single or dual rheostat available (dual rheostat included with jackets and vests)