- Updated with deodorization features and ultra-stretch fabric for comfort and ease of wear. - Lightweight yet warm. - 'HEATTECH' Ultra Warm is Approximately 2.25 times* warmer than regular 'HEATTECH', with a brushed interior for extra softness. *Based on CLO values, which indicate the thermal insulation of clothing. Compared to regular 'HEATTECH'. - The ultra-stretch fabric features HEAT RETENTION, Heat of Absorption, moisture-wicking, and deodorizing technologies. - The stitching and fit have been reviewed and updated for increased comfort.