Get the most out of every run and find your motivation with the heart rate tracking and wireless music streaming of the Garmin Forerunner 645 Music GPS. Setting itself apart from the standard Forerunner 645, this particular version holds up to 500 songs and streams your favorite tunes to any pair of Bluetooth ear buds or headphones (headphones are sold separately). It's hooked up with Garmin Pay wireless for cashless convenience at the checkout, so you don't have to bring cash or carry a wallet around town. Wrist-based heart rate monitoring and run-savvy measurements give you all the tools you need to get faster and more fit, regardless if you're training for an upcoming marathon or just getting back in shape after a long winter. Pair this Forerunner 645 Music GPS with Garmin's Running Dynamics Pod (not included) to gain a whole host of key running stats, including ground contact time balance, stride length, and vertical ratio. Besides its running and music streaming features, the Forerunner 645 Music GPS is loaded with ANT+, Bluetooth Smart, and Wi-Fi capabilities, so you can wirelessly sync it with a host of compatible devices, including iPhone and Android smartphones. And speaking of wireless syncing, it works seamlessly with the Garmin Connect app, so you can view all your exercise stats on a smartphone or computer for an in-depth analysis of your running stats and exercise output.