sentences:  The AP9 is a self-loading pistol using the blowback mechanism with a double-action trigger, has a rotating safety/decocking lever on the left side of the slide, and is equipped with a firing pin safety mechanism, which prevents the firing pin from striking the primer of a loaded cartridge, unless the trigger is pulled.Field-stripping the pistol for cleaning is accomplished identically to the Walther PP pistol.The frame is made of aluminum alloy and the slide is made from steel.