wearable digital electronic devices in the nature of a wearable activity tracker for detecting, storing, reporting, monitoring, or transmitting information regarding hydration status during physical activity not for medical use; downloadable computer software for wireless data communication for receiving, processing, transmitting, and displaying hydration status; downloadable computer application software for smart phones and mobile devices for tracking, monitoring, receiving, processing, storing, transmitting, and displaying information regarding hydration status, not for medical use