Complete head tracking systems containing sensors, point models and software, which is to say everything necessary to bring about head tracking save for a personal computer, can be found on the market. In most cases these systems are characterized by better sensor resolution, wider angle sensors, better filtering, higher coordinate refreshing frequency as well as on board coordinate computation which decreases the work load of the computer on which the client software is being run, but, as compared to the systems users build themselves while using free or commercial software and off the shelf webcams, have a higher price: