This is my Range-Enhancing Tactical Anti-Reflection Device (Killflash), or "RETARD" for short.

This part - like the name implies - reduces the angle of reflection of of the optic's glass down to a tighter angle. Tested snug fitment on two separate Trijicon MRO's, as their bodies are forged and there are slight dependencies on each copy of the optic.

Print in anything that can take high temperatures if you want to put it on a fighting rifle, doesn't necessarily need to be strong filaments as it doesn't take any stress past tapping it onto your optic.