The Rock River Arms Flip Front Sight Gas Block Assembly is a good option for some AR builds, especially when you know you will be using optics but still want backup iron sights. It features three sling swivels and a short Picatinny rail segment in place of a bayonet lug. The sight folds out of the way when not in use.
Specifications and Features:
All steel construction
Fits .750" barrels
Two piece design allows it to be installed with pinned and welded muzzle device
Sight folds with touch of a button