FINIS Aqua Pulse Heart Rate Monitor Real Time Audible Heart Rate is announced into your ear as you move; no need to pause and look at a watch Bone Conduction Audio Announcement verbally conveys your heart rate through your bones into your inner ear; no ear buds needed Fully waterproof made for swimmers by swimmers; all buttons are waterproof Infrared Sensor Technology picks up heart rate through your earlobe Easy Attachment, no chest strap or watches needed; just slip inside your goggle strap