While many weapons are equipped with BUIS (Backup Iron Sights) for emergency use in the event of a scope failure, they require the removal of the scope before the BUIS can be flipped up ready for use. With ERA-TAC's Backup Sights there is no need to remove the scope because they are directly mounted to the top of the scope via our UNIVERSAL-interface. The weapon remains continuously available for use even in the event of a scope failure.