These shirts are designed to keep you cool, dry and comfortable, while providing flame resistant protection. In addition to providing flame and arc protection, shirts also offer antimicrobial protection to the wearer by preventing bacteria build up and reducing odor. Tubular T-Shirts are moisture wicking and fast drying. These 5 oz. shirt are extremely soft and will not shrink, pill or lose color. Tubular T-Shirts have an arc rating of 4.5 cal/cm2, which meets NFPA 70E Hazard Risk Category 1.