Designed to pair with TomTom Multi-Sport and Runner GPS Watches, as well as Bluetooth smart-ready devices, the TomTom BT Heart Rate monitor accurately measures your heart rate--so you can be better equipped to find your exercise sweet spot. Through precisely noting your maximum heart rate before you hit the wall, you'll be better equipped to push your personal exercise limits the next time you train.
Serious? Only 62.99 for the best additional. I'm gonna purchase one also for my dad.