This is the Deathstroke mask from Arkham Origins. In this remix I added strap holes to the mask and the back piece.
This mask was sized for an adult male. It is 10% larger than the orginal.
Note : If you printed the my original Deathstroke mask this back piece will fit it. You will just need to scale this back piece down 10% from what you printed the original. So if you printed the original at 100% the back piece will need to be printed at 90% to be at the same scale.