The RHYTHM Bluetooth Armband Heart Rate Monitor attaches to your forearm for wireless communication with your smartphone or other device. Working with the innovative RHYTHM App, the Bluetooth Armband monitors your heart rate and so much more: calories burned, speed, distance, pace as well as controls music, video playback, responds to voice commands and records voice memos on supported iPod and iPhone models. Featuring integrated buttons, you can adjust the volume by just by pressing ?+?, navigate favorites on your playlist, play/pause, next/previous by pressing the ?center? button and easily activate the VoiceOver feature on the iPod Shuffle 3rd Generation. The RHYTHM Bluetooth Armband Heart Rate Monitor comes in sizes large (16?) and small (10?).