The Thermal Swim Shirt provides warmth to swimmers by trapping body heat with its unique BiPoly fabric. Made from a strong, yet lightweight material, the Thermal Swim Shirt conforms to a swimmer's upper body without restricting range of motion. Used over time, the slight drag effect of the Thermal Swim Shirt will also build endurance and strength. The Nobel Prize-winning Polyolefin fibers provide UVA, UVB and Antibacterial protection, and is chlorine and fade resistant. HEAT-TRAPPING: Traps body heat with its Nobel Prize winning Polyolefin fibers CONFORMS TO THE BODY: Allows for a full range of motion during all four swim strokes UV PROTECTION: Provides UVA, UVB and Antibacterial protection (SGS Certified) DURABLE: Chlorine and fade resistant; machine-washable INCREASE ENDURANCE: Wear repeatedly to build strength and endurance in the water