ThermoVest heated vest can be used as liner or regular vest. Micro thin quilted material, multiple heating zones on back and chest.ThermoVest Re-chargeable 8000 mA power bank that quickly charges and provide regulated even heat for hours. 3 Temperature Control Options provide Constant Heat on high for up to 3 - 3.5 Hours _ Low Medium setting up tp 7 - 7.5 Hours. Adjustable Keypad temperature control with 3 temperature settings. Use alone as heated winter vest or as a heated liner under a jacket. Great for when you're veering down the slopes or cheering at the stadium, While Biking, Skiing, Fishing, Snow Plowing, and Walking in a cold weather Etc.