This paper model is a custom texture Helmet of the Enclave Power Armor (Advanced Power Armor Mk II) [it looks like the helmet of the Advanced Power Armor], based on the Fallout 3 video game series, the papercraft was created by Gardian. There is also a Fallout 2 - Advanced Power Armor Mk II Helmet Papercraft on the site.
The Enclave power armor is a model of power armor used exclusively by the Enclave military forces, developed after the Great War to rival that of the Brotherhood of Steel. It is composed entirely of lightweight composites rather than the usual combination of metal and composite plates. Its design is substantially different from the earlier model using the same designation, but using a different helmet, and lighter materials.
You can download the papercraft model template here: Fallout 3 - Enclave Helmet Papercraft Free Download