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.