HEATR® Tundra Base LayerContoured Fit Will keep you warm even in temperatures from 0 to 75 F Wsi's #1 base layer. Great for layering to throw on under anything and it won't add bulk, while keeping you extra warm Base layer for minimal bulk and moderate warmth HEATR is located throughout the entire shirt for enhanced thermal warmth Flat inner seams for added comfort Care Instructions: Machine wash cold, gentle cycle, with like colors Line Dry