All human weapons
The Iron Sight is the standard sight for most weapons. It is characterize by a single bead, usually glowing green, on the front of the weapon, surrounded by two other beads closer to the back. The center bead is used to aim, while the other two, used to keep the center one level. The appearance of these beads vary between weapons.
Both parts of the sight, the front center bead and the back side beads, are removed from the weapon when another sight attachment is used. This includes the Laser Sight, even though it is attached right beneath the barrel.
Most weapons has color tip on its iron sights, which help users to detect the position of beads while cloaking. Although it harder to targeting than Reflex Sight, it has higher peripheral view and makes user more aware to enemies outside of the sight view. To aim, follow the front bead color tip and make sure the rear bead color tip has same horizontal position with front bead.