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Backup Iron Sights
BUIS Optics3.png
Category Attachments > Optics
Used By M4-A1
Size 1 Slot
Weight 644 g (1.42 lb)
Absorbency 0
Type Iron Sight
Magnification 1x
Variable Zoom No
Zeroing 25m - 200m (200m default)
Use Seperately No
Locations Military
Rarity Very Rare
Standardized rail-mounted backup iron sights designed for M4-A1 assault rifle. — In-game description

The Backup Iron Sights is a non-magnifying, iron sight for the M4-A1 in DayZ Standalone. Since it is intended for use with the M4-A1, it is the only gun it can be used on. Since it provides no performance improvements or magnification and is intended only as a backup, attaching the Backup Iron Sights to the M4-A1 is not recommended. Although the sight less obstructive that the M4-A1 Carry Handle Sights.



  • Before 1.03, the Backup Iron Sights was named the BUIS.
  • The BUIS was temporarily not spawning in patches 0.63 to 1.02, awaiting reimplementation.
  • At one point, it was possible to equip the BUIS sights to the Crossbow, SG5-K, USG-45 and the LAR. This ability was later removed.
  • This model is based on the MaTech BUIS which is currently the standard issue M4 rear iron sight for the U.S. military.