Fully Printable Mechanical Assembly:
The side of the helmet features a fully printable, gear driven hinge that allows the helmet to open up and reveal the face, just as is shown in-universe. This mechanism allows the face plate to slide up the helmet and the neck shield to slide down the helmet. 
 
There is optional magnet support in the face plate and the neck shield to assist in keep the two pieces securely sealed and provide a satisfying *snap* when closing the helmet. See the included video to hear an example.
 
Two Helmet Variants:
This helmet features two distinct variants. The Mechanical helmet features all the gear mechanisms shown in the assembly and demo videos. This helmet is designed around the mechanical hinge mechanism and thus the face plate is mounted onto the hinge rail and the neck shield is mounted via the neck shield corner gear.
 
The second variant is a simplified version of the helmet with a static face/neck shield. The neck shield is mounted via static pegs in the main body of the helmet and the face shield can be attached fully magnetically to the helmet and thus is still removable. Otherwise, printable clips are also included to allow the helmet to be fixed in place. This helmet has a hollow hinge unit to allow for additional storage of fans, speakers, etc. Additionally, because the mechanisms of the functional hinge are not included, this helmet has more space inside/can be printed smaller.

Both helmets come with their own unique sizing ring to help you understand what size of helmet can fit onto your head.
 
Both helmets have alternate sliced versions of the larger pieces such that any printer with at least a 255^3 mm build volume can print the helmet.
 
All ornaments including the Fleur De Lys and Face Shield Studs are separately printable. There is also a printable template to help you space the studs.
 
Easy-Install Visor System:
All Face shield variants include tabs on each end of the visor holes to allow you to fit a thin sheet of your reflective material of choice in the helmet. Printing the template to size your eye lenses, will ensure their own arching tension hold themselves in place without the need for glue or tape.
 
Detailed Build Guide:
Detailed instructions/tips on building this helmet can be found in the dedicated build guide. Additional pictures/videos can be found on print orientation, assembly, etc.
That guide is located here