More ideas from Peter
Knowing what your splits should be is really important if you’re trying to run a certain time — especially for longer distances. These bracelets, available in a wide range of distances and goal times, save you the trouble of memorizing every split or trying to do the math on the fly.

Pacebands 21 Cool Gadgets That Every Runner Could Use-- I've been using marker on my wrists for pace timing this is a little nicer than the magic marker :)