The Garmin Forerunner 305 GPS unit with heart rate monitor. You can keep tabs on how hard you're working, making sure to neither over or under exert yourself. (Photo by Walter Cruz/Dallas
Review of Garmin Forerunner 305 | DC Rainmaker
Garmin Forerunner 305
GARMIN Forerunner 305 GPS Receiver | eBay
Wrist-mounted GPS offers real-time training
Amazon.com: Garmin Forerunner 305 GPS Receiver With Heart Rate Monitor (Discontinued by Manufacturer) : Garmin: Electronics