Bare 5mm Reactive Men's Fullsuit Construction: Elastek Full-Stretch Nylon-2 Neoprene Celliant Liner Infrared Technology Seams Glued & Taped Celliant Fabric Liner: Highest Degree of Warmth Enhanced with 13 Thermo-Reactive Minerals Woven into Fabric React to Body Heat Converting it to Infrared Energy Reflects it Back to Body, Increasing Circulation and Body Warmth Velcro Adjustment Collar: Booklet-Style Cover, Protect Suit from Snags & Pilling Seamless Underarms for Superior Comfort and Mobility