The stopwatch is a fairly self-contained system which is why it is so popular. But you can use a number of accessories and other tools with it to enhances its performance and maximize the benefits. Most stopwatches can be worn with a lanyard, clip, or other accessories so your hands can be free most of the time.
You can also use the results of your stopwatch times with other tools to track miles, calories, heart rate, and overall workout performances. All in all, the best stopwatches will offer the features you need!