Medical devices, instruments and articles, namely, Ganzfeld Open-Eye Goggles in the nature of low frequency electric therapy apparatus; mind machines, namely, machines using sound and light to alter the brain wave frequency of the user in the nature of sensory light and sound therapy units; stress management devices, namely, apparatus that utilize light, sound, and vibration for relaxation therapy in the nature of sensory light, sound, and ultrasonic therapy machines and apparatus; learning aid devices, namely, apparatus for increased receptiveness of study content in the nature of sensory light and sound therapy units; medical biofeedback devices, namely, biofeedback sensors based on galvanic cutaneous reactions, biofeedback sensors based on muscle contractions, respiration biofeedback sensors based on measurements of skin temperature, biofeedback sensors based on measurements of the heart rate and electroencephalogram biofeedback sensors