>> that's it. no other wires here. >> reporter: the little black box sending data straight to your smartphone. state-of-the-art. >> yeah. >> reporter: hard working ball boys like eric, test driving the prototype tees expected in stores next year. let's see how fast i can get eric's heart rate up. giving this guy a workout. all right. well done. how do you feel? >> i feel great. >> reporter: you're sweating. >> a lot. >> reporter: do you think you're going to be a lot more fit at the end of the tournament? >> i hope so. >> reporter: pole low and other sportswear and tech companies trying to cash in on a wearable technology craze that has hundreds of thousands of americans monitoring their activity on fitness wristbands. >> because it is not just small tech companies talking about this anymore. a giant apparel brand. >> reporter: but for all that tech it is the simple things that keep this ball boy happy. >> can i test and see if your shirt is still dry? >> yeah. >> and it is.