It is made of a rugged Glass Filled Polymer just like the pistol grips of the AR15.
It fixes some of the deficiencies that are inherent with this optic.
1) In low light (twilight) or night situations when the Reticle is hard to see, just turn on the REM ACOG and it illuminates the Reticle to your preference. The Rheostat has 11 light settings. The low #1 setting is best for twilight or night situations (no more taping a glow stick to the fiber optic)
2) When you are in a dark area looking out into bright sunlight it is hard to see the Reticle of the TA31 ACOG. Just turn on the REM ACOG to its highest setting #11 and the Reticle will glow for an easy sight picture.
3) The other problem the REM ACOG fixes is the Reticle bloom that occurs in bright daylight. The REM ACOG covers just over half of the Fiber Optic (reducing the light input) so in bright daylight you can see the Reticle more clearly without burning out you eyeballs. (No more putting hurricane tape over the Fiber Optic)
4) The REM ACOG also eliminates the need to replace a dead Tritium. Just turn on the REM to the #1 setting and you can clearly see the Reticle.
The REM ACOG is designed so the Trijicon TA91 Tennebrex Killflash Anti-Reflection Device can still be installed.
Retail price is $46.95 You can now pre-order them on my website https://m1bullpup.com/product/rem-acog/ They should be here by the end of February.
Standard picture sight of the TA31 ACOG
Picture sight with the REM ACOG turned on