3. Garmin Forerunner 305

Unlike the Timex Bodylink, the Garmin Forerunner 305 does not serve as a watch; since it packs its GPS device into a single component, it would be too large and heavy to wear all the time as a watch, anyway. The unit charges by locking into a cradle that plugs into an electrical outlet. The downside is that the charge only lasts for 10 hours. The unit also comes with a heart rate sensor strap that you wrap and attach around your chest.

The Garmin Forerunner 305, like the Timex Bodylink, has many features and functions that do a lot more than just gauge your speed, distance and heart rate. When setting up your profile, you are prompted to enter your sex, age and weight so that one of the functions can measure how many calories you burn during a workout.

You can also specify whether you are going to run, bicycle or do a different kind of workout that falls under the "other" category. While swimming was not listed, the manual said the unit was waterproof to a maximum of one meter (about three feet) underwater for a period of 30 minutes. However, I did not test how waterproof it was while swimming, as 30 minutes is a relatively short period of time and the guide warned that "prolonged immersion" could damage the device.

The unit offers alerts and options to aid with interval training, which are largely similar in function to those that the Timex Bodylink offers. You can program the device to sound alarms when, for example, you run a set distance, after a certain workout time period has elapsed, or when your heart rate reaches a maximum level. The data for each interval workout and session is stored.

One of the more unique training options is "Virtual Partner." In this mode, a small white figure appears on the monitor as you workout. After selecting a time and distance goal for a workout session, you compete against the virtual partner who is either ahead or behind your virtual self on the monitor, which appears as a black figure on the screen.

Again, the Garmin Forerunner is first and foremost a GPS device for gauging your speed and distance while running or during another aerobic workout. However, it also has navigation ambitions. After selecting the Map page from the main menu, you can follow your path on a map, complete with indications of your bearings of direction, longitude, latitude and altitude. Once a location is reached, you can mark the spot by specifying a place name to appear on the map page. You can also set it to trace your movements, so that you can follow a line on the map page that will lead you back to your starting point.

The map, however, is rudimentary and does not offer any information besides your bearings and direction, much like the first GPS devices that became available to consumers over a decade ago.

Too bad the charge only lasts about 10 hours or so. The navigation function would work well with a traditional map for hiking or could come in handy during an emergency if, for whatever reason, you were lost in the wilderness somewhere.