Profesionally reverse engineered eyepiece lens made of the same glass material and same coatings applied as the original lenses. Technically user replaceable with enough competence and the right tools. If your eyepiece lens has a crack or a tremendous amount of scratches, this replacement lens will fix that issue. 
 
These lenses are a must for anyone using ACOGs that are unable to be serviced directly by Trijicon. There is no other option to replace these lenses other than salvaging spare parts from donor units.
 
To perform installation- remove the 4 screws on the back of the optic. With an adjustable spanner wrench, flathead screwdrivers, or other tools, unscrew the retaining ring inside the eyepiece housing. Remove the first eyepiece lens you see inside the housing. Next, remove the second eyepiece lens that is exposed to the outside. Remember the orientation of this lens. Drop in the new lens into position and reassemble everything in reverse. 
 
For those who dont feel comfortable opening up their ACOG, you can send it in to have this installation performed on your behalf. 
 
Additional components such as the second eyepiece lens, prisms with and without reticles, and other components, can be manufactured upon request.