Fasten Mio's Fuse to your wrist for precise calculations of your heart rate, steps, calories, and distances ran and trained. Mio's Optical Heart Rate Technology uses world class algorithms to measure your heart's rhythm without using an uncomfortable chest strap. There are two heart rate zones for goal keeping convenience. The Fuse also tracks your steps, calories, distance, pace, and goal progress throughout the day. Mio encased the Fuse in soft, sweat proof, waterproof silicone for a harmonious blend of protection and comfort. Bluetooth Smart and ANT connectivity lets you record and share your progress on the interwebs.