As accurate as strapped EKG sensing, Mio™ Alpha features electro-optical lights that sense your pulse and track your heart rate. The ideal strapless continous heart rate monitor, it features heart rate zones with visual and audible alerts, timer, clock, data review, and simple two-button functionality. Rechargable by magnetic USB dock. Soft, comfortable silcone strap. Packs include monitors, 10-port USB hub, and a hard plastic case with custom foam interior.