O'Neill men's 24/7 sleeveless: Loose fit, breathable shirt, 30+ SPF Protects against sun fatigue and provides a breathable, cooling effect Engineered fit with strategic seam placement for comfort lets you be active in comfort - or just lounge around Not tight-fitting like typical Lycra rashguards, this sleeveless crew can be worn comfortably over a swimsuit or with boardshorts, or during active sports Tall sizes are 3.5 inches longer in the body. New for 2016: King and King-Tall sizes. King 1X is equivalent to 3X-Large, King 2X to 4X-Large, etc.