Headphones; Earphones and headphones; Computer hardware; Noise cancelling headphones; Wireless headphones; Wearable computers in the nature of smartglasses; Wearable computers in the nature of smartwatches; Digital electronic devices and instruments containing sensors for measuring, displaying, storing, or transmitting biosignals, physical parameters, and other physiological data; Data tracking units, not for medical use, comprised of a head-worn device for measuring, tracking, and monitoring electroencephalogram (EEG), electromyogram (EMG), electro-oculogram (EOG), electrocardiogram (ECG), photoplethysmogram (PPG) signals, and for measuring, tracking, and monitoring accelerometer data, and gyroscope data; Downloadable music via the internet and wireless devices for helping users focus; Downloadable software containing music that adapts to sensor data;Downloadable software for creating and playing music; Downloadable software for listening to audio recordings with instruction and guided meditation in the fields of concentration, motivation, stress management, goal achievement, productivity, and mental health