The open back and slightly loose fit creates a breezy feel with more cooling as your run heats up. The back part is open so you can show off your cute sports bra or whatever. | The cuffs have elasticity and you can push them up to the elbow when you exercise, provide more freedom. Elastic cuffs make sure the cuffs will not go up during a workout. | OCCASION: Bestisun Long Sleeve suitable for yoga, exercise, fitness, gym, running, any type of workout or everyday use. Our active shirts combine fashion, function and performance. | 95% Rayon 5% Spandex. Super Soft and Comfortable. | NOTICE: Please check the size chart in the description below or picture before ordering instead of the default amazon size chart. Please Click this Website to find more product. https://www.amazon.com/bestisun