Rukka t-shirt for men. Regular fit. No irritating side seams. The fabric quickly wicks moisture away, keeping the skin dry and feeling comfortable. The product's stretch material flexes in four directions, providing complete freedom of movement. UPF (Ultraviolet Protection Factor) indicates how much of the sun's UV radiation passes through the fabric. UPF 30 fabric allows about one-thirtieth of UV radiation to pass through. The UPF value is based on the fabric's tested UV performance, achieved through the fabric's structure and weaving method, not chemical treatments.