For example, ever wonder how steep that hill on Sunset is? Me either, but now I know....I wore this thing during the Winterstart races and made some pretty cool maps of the courses.
Winterstart Classic Race
Winterstart Skate Race
And last Sunday I hit nearly 20mph on a few of the downhills. I think I'm going to have to go back and try for 25.
The device has a nifty heart rate monitor too, which I haven't used too regularly. Sometimes, I don't care to quantify how hard I'm working....