The Walther P99, which is available in either 9mm Luger or .40 S&W, is simply one of the most unique duty pistols available on the market today. That’s because the P99 is a striker fired pistol (much like a Glock), but it also has a double action/single action trigger mechanism (meaning the first shot is long and heavy, and all subsequent shots are short and crisp), which is normally something that you would only expect on a hammer fired pistol.
But the P99 also has a third trigger position called the AS mode. When you pull the slide back around a quarter of an inch, the gun is cocked, but the trigger remains in the double action position. However, the trigger pull is now much lighter to pull, while also being safer to carry than if it were in the single action position. It truly is a marvelous system, and one that is highly under appreciated.