from Wikipedia: Trigger actions While the earlier standard versions of the 24/7 pistol came equipped with double action only triggers, the later Pro models and some of the OSS pistols sport double action/single action triggers, allowing for a safer and harder long double action initial trigger pull, with the action for all subsequent shots being cocked by the first, resulting in a lighter and more concise single action trigger pull. This system allows for two major advantages, one being that the pistol can be safely carried with the safety off for faster first shot capability, and the second being that if a round misfires, the trigger can be quickly pulled again in double action mode, repeating the attempt to fire the recalcitrant round. This type of DA/SA system, pioneered on such firearms as the Walther P38 and PP/PPK, is much faster and simpler than the standard tap, rack, bang method of clearing a dud cartridge.[5]