Knights Armament KAC Mk11 folding front sight, push button (new old stock)
This is the now discontinued front folding sight for the Mk11 Mod0. The sight sits atop the Mk11 or M110 gas block, and folds backward into the front free floating rail.
Note: Charlies has a handful, but plans to use for complete Mk11 barreled upper receiver groups. That could change if we are able to procure more.