We had the need for a device to hold a subjects head in one place firmly for eye tracking studies, but without the claustrophobic feeling associated with being unable to 'get out'. This clamp firmly holds the subjects head, but allows them the freedom to withdraw at any time. It is self centering, and is very well tolerated. It has thus far fit every head we have tried, from small children to "fat head adults".This thing needs support to print correctly as there are significant overhangs. Print 2 brackets and mount with the shorter arms towards the middle. This thing was modeled in TurboCAD 17.