This is a full size and wearable Halo:Reach Marine helmet modeled after the base helmets.

This helmet fits a 24" head by default and is split so that it will fit on any 256x256x256 bambu sized printer or larger. All pieces either snap together or had registration keys to be glues. I would suggest adding velcro or elastic straps to the interior cheek pieces so the helmet is easier to put on and off.