by Timex

Does it Work? Perfectly, but the GPS unit is still too big to forget you’re wearing it.

Cost: $300;

Hardcore athletes–cyclists, marathoners, triathletes–have long been closet geeks, relying on technology for a constant stream of lap times, speeds, heart rates and other data. These ultra-tuned wonks should be thrilled, then, about Timex’s Bodylink: the first device that adds GPS to traditional sports electronics to precisely chart distance, pace and heart rate with one simple unit.

The system works exactly as billed. Velcro the GPS receiver to your arm or belt and it transmits speed and distance to the watch; strap the heart monitor to your chest and it sends beats per minute. Data flows flawlessly, no matter how fast you’re moving. And its PC interface ($75) is seamless. Athlete-geeks, rejoice!

So why am I ambivalent? One reason: At about the size of an iPod, the GPS unit is distracting. Until these devices get smaller, the Bodylink feels more geek than athlete.