Developed by Dr. Jonathan D. Wirtschafter as a device to help educate colleagues in testing Strabismis —an eye condition that causes the eyes to move out of alignment vs both looking straight one eye goes off to the side. In this test you control a knob that presents various scenarios and the person is supposed to diagnose the condition. A button is then pushed to reveal the result. A very unique custom demonstrator developed by the doctor. I am certain that these were not mass produced items but rather low run and to be used as teaching aids. Dr. Wirtschafter was a Harvard graduate and spent many years working as director of Neuro-Ophthalmology in Twin Cities Mt. Sinai along with teaching. An innovator and educator that contributed much to the evolution of medicine we can see such an example with this interesting teaching device. Measures: 15” H x 12.5” W x 8” D comes with cord and system seems to be in working order.