Quick Take: Lance Armstrong uses this German-designed training computer during his races. While CicloSport's feature-packed device has been widely adopted by the cycling community, it's meant to cater to a variety of athletes, from triathletes to snowboarders. Made of plastic with a Velcro strap, the HAC 4 can be worn around your wrist or clipped to your bike's handlebar mount (especially nice if you want to use it during a triathlon). The HAC 4 measures and tracks data on your heart rate, your altitude, your speed, your mileage, your cadence, and your average and max performance. It also offers a sizable list of customizable features and data views--up to 57 functions in total. And its memory is impressive; the HAC 4 can store up to 64 hours of data, which you can then download to your PC for analysis using the included software.