GPS receivers have become so compact that it's now feasible to wear one on your wrist. GPS device manufacturers like Garmin and others have expanded their product repertoire with more unique options, such as the Garmin Forerunner series of wristwatch-sized GPS devices. We took the Forerunner 305 for a jog and were pleasantly surprised at how well it grabbed and held a signal--even indoors.

The 305 is designed more for training than for navigating, but it features some rather advanced GPS options including being able to view your location on a crude but serviceable map as well as plot directions to your starting point or other waypoints--it can store 100 locations. It's built around a SiRFstarIII GPS receiver, and it captured a signal in just a couple of minutes the first time we fired it up (and within seconds on subsequent startups).

This GPS device is about twice the size of a typical sports wristwatch, or roughly the same size as a wrist-bound heart rate monitor. Speaking of: the 305 features a wireless heart rate monitor that can sound an alarm when you reach your maximum or minimum heart rate.

The training software that comes with the 305 lets you load your results onto your PC so you can keep track of your progress. You can also plot out paths and workout routines that the GPS device can lead you through. But one of the best features for improving performance is the ability to compete against your past results or against a "virtual partner"--the 305 lets you know whether you're ahead or behind and by how much. Definitely a great motivator.

It keeps track of your pace, your lap times, your current elevation, and how many calories you've burned on your workout. The 305 is also compatible with Garmin's GSC 10 cadence sensor (a $60 accessory) for bicycles, so it keeps tabs on your cycling cadence while you're on the move.

The 305 is water resistant, so you don't have to worry about it getting damaged in the rain (or if you're a heavy sweater). It's one of the more advanced wrist-top GPS devices out there, and its price tag may be a bit much for some users. But if you're looking for a GPS-enabled personal trainer with all the bells and whistles, the Garmin Forerunner 305 is a great one to wear.

Pros: Well designed, advanced GPS and training features
Cons: Larger than a typical workout watch, expensive

Warranty
1 year, limited