This is a fairly new offering from Czech arms maker CZ, and stands out on this as one of the only hammer fire gun thus far. Thus it can be fired single to double with the hammer cocked. It also has a smooth double action pull on the first shot.
The P-09 also has a de-cocking mechanism that allows you to toggle back to double action with a round in the chamber.
Perhaps the standout feature of this gun is the ammo capacity, an impressive 19+1 rounds. Sheesh, you’d better be able to hit you target with that many shots.