one-piece is made with fabric that reflects and absorbs the infrared rays contained in sunlight, blocking out heat. It's made with multi-functional material that also has UV protection and is sweat-wicking and quick-drying. It creates a slender, vertical impression without showing the body lines. It's easy to wear, just slip it on. The contrasting panels and moderately thick material give it a neat look. The three-quarter sleeves make it suitable for all seasons. It also comes with a convenient Pocket.