This unit is surplus from a large educational institution.  The Eye Trac 310 has a 15-pin plug for connecting to the ASL Controller (Controller not included).  See the photos for content and condition.  Untested, for parts or repair only.
Applied Science Laboratories (ASL Eye Tracking) in Bedford, Massachusetts, is the recognized authority in the field of eye tracking technology. The Mobile Eye‐XG and a comprehensive EYE‐TRAC® suite of versatile solutions designed and manufactured by ASL are used worldwide in academic research, market research and industrial markets. ASL's innovations include: desktop optics with head motion compensation, portable, wearable devices, eye/head integration, long range optics for fMRI and revolutionary data analysis options. With dynamic, scalable and innovative solutions delivered with world‐class customer support, ASL continues to be the complete eye tracking hardware, software and professional services provider.