Diamondhead USA Gas Block Front Iron Sight Rail mounted, Diamond folding sight - incorporating the patented Diamond-shaped upper housing Mounts directly to a railed gas block, providing secure and solid sight attachment to barrel Allows for sight stability, eliminates potential handguard movement and holds a true zero Taller sight to compensate for (below receiver height) gas block Patented Diamond-shaped Housing frames & centers the target with speed and ease Mounts directly to a railed, reduced height gas block, providing secure and solid sight attachment to barrel Allows for sight stability, eliminates potential handguard movement and holds a true zero Taller sight to compensate for (below receiver height) gas block STAG Arms Model 3/AR15/M4 & AR10/.308 gas block options