Knights Armament Company M4 Front Sight, Fits Picatinny, Black Finish, Folding Front Sight for Top Rail 99051-BLK
The M4 folding front sight is a low-profile backup sighting solution that is designed to be attached to the top rail of a rifle's handguard. When stowed in the folded position" the M4's sight base extends back to envelope the front sight leaf on the right and left side" helping to protect it from damage.