HEATTECH Ultra Warm is 2.25 times warmer than our regular HEATTECH. Easy to use as a T-shirt, now with long sleeve. Now in plastic-free packaging. - Bio-warming, insulating, moisture-wicking, and moisturizing comfort features. - Material is stretchy and maintains its original shape well. - The long sleeves have been changed to a looser fit so that it can be worn on its own.