This papercraft is a life size Mordred Excalibur Helmet, an alternative Helmet Item for Excalibur, from the free-to-play cooperative third-person shooter video game Warframe, the paper model is created by Sinner. The size of finished model is about 320 (H) x 315 (W) x 210 (D) mm.
Its blueprint can be acquired from Alert missions. To equip your newly bought or crafted helmet, go into the "Arsenal" page, then click on 'Appearance' tab, the Helmet will be the first item in the section labeled 'Physique'.
You may download this papercraft template here: Warframe - Life Size Mordred Excalibur Helmet Papercraft Free Template Download