This Ariat men's Calvin long sleeve button down performance shirt has been designed for the working man, whether you are on a horse or on the ground. The technology features in this shirt will keep you cool, dry, and comfortable.The MMT technology pulls moisture away from the skin and transports it to the fabrics outer face for quick evaporation. The SPF technology is a fabric treatment that utilizes technology to protect from harmful UV rays. Ariat's western sleeve technology creates a system that allows for freedom of movement without worrying about sleeves riding up or shirt tails coming un-tucked. Ariat has made performance enhancing changes to their riding boots and apparel to give athletes an edge. Their forward thinking and performance lines outfit today's most avid equestrian riders and enthusiasts.