59FIFTY: Our original, fitted cap. A revolutionary performance headwear worn by all MLB clubs throughout the entire baseball season including Spring Training, Batting Practice & select regular season games. Always at the forefront of innovation, the 59FIFTY is infused with the latest NE TECH materials to keep players cool & comfortable on the field of play. Made with a new state-of-the art performance diamond patterned fabric, the first-class Diamond Era 59FIFTY is light & breathable. The premier cap also features SOLARERA-, 50+ UV protection that helps deflect the sun's unforgiving rays & COOLERA- technology that wicks away sweat to keep players comfortable, allowing them to focus on optimal performance.