The 24/7 Pro is SA/DA, however not all of the Millennium Pro's are. The 2nd Generations of the Mil Pro are DAO. The 3rd Gen of the Mil Pro is SA/DA. The most easily identifable indication of the models are the dovetail Heine Sights. All of the 24/7 Pro's are dovetail sights and SA/DA. The 2nd Gen Mil Pro's have the screw on sights, the 3rd Gen have the dovetail sights. Hope this helps.