No longer offered by Centurion. This is the 12" C4 rail that has a cutout for a FSP and extends past to allow mounting of devices at 12 O’clock. I purchased it unused from a member here and installed it on an upper I was building. Never used it and decided to go a different route. Couple slight wear marks but excellent overall condition. Will ship in a different Centurion box I have laying around.
SOLD