The attention-tracking device (ETD) is a headmounted device, designed for measurement of 3D eye and head movements below experimental and natural situations. The tracker permits complete measurement of eye movement (three levels of freedom) and optionally head motion (six degrees of freedom). It represents a tool for the investigation of sensorimotor iTagPro portable behaviour, particularly of the vestibular and oculomotor methods in both health and illness. It was originally developed by the German Space Agency (DLR) for use on the International Space Station (ISS) and was uploaded to the station as part of the joint European / Russian area programme in early 2004. The device was designed by Prof. Dr. Andrew H. Clarke (Vestibular Lab, Charité Berlin) together with the companies Chronos Vision and Mtronix in Berlin and integrated for [iTagPro tracker](https://higgledy-piggledy.xyz/index.php/13-4293_-_Tracking_Device_Search_Warrant